Freshly made Cheddar cheese is hard, tough and elastic and lacks characteristic cheese flavor. In this condition it is called "green," unripe or not cured. Before the cheese is ready to be eaten, it passes through a complex series of changes which are collectively known as ripening. In the ripening process the texture becomes soft and mellow and the characteristic cheese flavors develop. Cheese ripening must be considered from two view-points, first, the changes taking place inside the cheese and secondly the outside conditions necessary for ripening. Some of the chemical changes during ripening are known, while others are not understood. The different agents causing ripening, and the constituents of the milk, will be discussed.

231. Fat.—Numerous investigations have been made to ascertain what chemical changes the fat undergoes in the ripening process. Suzuki,103 in studying the fat, found no enzyme capable of producing lactic acid or volatile fatty acids. However, these acids were found in increasing amounts during the ripening process and after the lactose had disappeared. Acetic and propionic acids reached a maximum at three months and then decreased, while butyric and caproic acids continually increased during the experimental period covered. Formic acid was detected in the whole-milk cheese only at the five and one-half month stage. In the judgment of the experimenter the principal source of acetic and propionic acids was probably lactates. Traces of these acids may have had their origin in protein decomposition or further fermentation of glycerine. The principal sources indicated for butyric and caproic acids were fats and proteins.

The distillate from the experimental cheese was designated "flavor solution" and contained alcohols and esters, giving a close resemblance to the cheese aroma. The "flavor solution" from the mild whole-milk cheese contained esters made up largely of ethyl alcohol and acetic acid, while from the more pungent skimmed-milk cheese the esters were largely compounds of ethyl alcohol and caproic and butyric acids. The alcohol may have come from the lactose fermentation. It appears to be an important factor in flavor production. The agencies operative in the production of volatile acids and syntheses of esters are as yet undefined.

232. Milk-sugar.—The milk-sugar (lactose) is changed into lactic acid by the lactic acid-forming organisms, within the first few days after the cheese is made. This acid is combined with the other constituents as fast as it is formed. After a few days, the milk-sugar will have entirely disappeared from the cheese.104 The relation between the milk-sugar and lactic acid is very close. It is necessary that milk-sugar be present in order later to have the lactic acid develop.233. The salts.—Just what changes the salts105 undergo or how they combine with the other compounds is not definitely known. It is supposed that the calcium salts first combine with the phosphates and later, as the lactic acid is formed, they combine with the lactic acid, forming a calcium lactate.

234. Gases.—In the process of cheese ripening, gases are formed, the commonest being carbon dioxide.106 Exactly how this gas is formed is not known. It may be due to the formation of lactic acid from the milk-sugar or to the living organisms in the cheese.

235. Casein or proteins.—Complex ripening changes in the cheese take place in the casein compounds or proteins. Because of the complex chemical nature of the proteins and the various agents acting on them, it is difficult to follow these changes. This has led to different opinions regarding the ripening process. The various compounds thought to be formed from the casein or proteins are as follows:107Paracasein (formed by the action of the rennet on the casein). Insoluble in brine and warm 5 per cent salt brine.

Protein. Soluble in warm 5 per cent salt brine.

Protein. Insoluble in warm salt brine or water.

Paranuclein. A protein soluble in water and precipitable by dilute hydrochloric acid.

Caseoses and proteoses. Protein derivations soluble in water and not coagulated by heat.

Peptones. Protein derivations simpler than the proteoses, soluble in water and not coagulated by heat.

Amido acids. Protein derivations soluble in water, least complex except ammonia.

Ammonia. The simplest protein derivations.

From the discussion of the constituents in the milk and cheese, it is evident that practically all the principal ripening changes are concerned with those taking place in the proteins.

236. Causes of ripening changes.—Authorities disagree as to the exact agents which cause the ripening changes. Some think they are due to the action of the enzymes in the rennet and those secreted in the milk. Others hold that these changes are due entirely to bacterial action. A combination of the two seems probable. The action of the rennet extract renders the casein insoluble and in the ripening process the proteins become soluble, the degree depending on the length of time the cheese is ripened. The amount of water-soluble proteins and protein derivatives is used as a measure of the extent of cheese ripening, considered from a chemical standpoint.

237. Action of the rennet extract.—Some authorities hold that rennet extract contains two enzymes, rennin and pepsin, while others think it is a single peptic ferment. These enzymes produce effects108 closely related to, if not identical with, those of pepsin in the following particulars: neither the rennet enzyme nor pepsin causes much, if any, proteolytic change except in the presence of acid; the quantitative results of proteolysis furnished by the rennet enzyme and pepsin agree closely, when working on the same material under comparable conditions; the classes of soluble nitrogen compounds formed by the two enzymes are the same, both quantitatively and qualitatively; neither enzyme forms any considerable amount of amido compounds and neither produces any ammonia; the soluble nitrogen compounds formed by both enzymes are confined to the group of compounds known as paranuclein, caseoses and peptones.

Rennet exerts a digestive effect on the casein109 which is intensified by the development of acid in the curd. The soluble nitrogenous products formed in Cheddar cheese by the rennet enzymes are the albumoses and the higher peptones. Experiments show that no flavor develops until the amido acids and ammonia are formed. When the rennet enzymes were the only digesting ferments in the cheese, there was no trace of cheese flavor. This is probably due to the fact that the rennet enzyme changed the casein into caseoses and peptones but did not form amido acids and ammonia. Some authorities110 think that the enzyme galactase carries the ripening of the protein from this stage. The question arises whether these intermediate compounds must be found before other agents can form the amido acids and ammonia.

TABLE XV111

The above table shows that the more rennet extract used the faster the cheese cures, measured by the amount of water-soluble nitrogen compounds formed in the cheese.

238. The action of the bacteria.—Authorities112 disagree as to the groups of bacteria found in Cheddar cheese. This may be due to lack of proper classification. Some of the groups are: Bacterium lactis acidi, B. coli communis, B. lactis aerogenes, B. casei, Streptococci, B.113 Bulgaricum and Micrococci. Authorities agree that the B. lactis acidi group is the most prominent. This group makes up 90 per cent or more of the total bacteria flora of the cheese in the early stages of ripening. In the course of a few weeks, however, this group is largely replaced by the B. casei group.114

TABLE XVI

From Wis. Bul. 150.

The large number of bacteria in the cheese is very striking. The number as given in the accompanying table is not that actually in the cheese, as it is very difficult to obtain the sample in suitable condition for plating.115

The principal action of the lactic acid-forming bacteria in the cheese ripening is the changing of the milk-sugar or lactose into lactic acid and the formation of small amounts of other substances, such as acetic, succinic and formic acids, alcohol, aldehydes and esters and some gases, carbon dioxide and hydrogen. While the amount of these substances other than lactic acid is small, it is thought that the effect of these on the cheese may be important. Heinemann shows116 that lactic acid exists in two optical modifications, the levorotatory and dextrorotary acids. In cheese they are usually found in the inactive or racemic form, the levorotatory and dextrorotary acids being present in equal amounts. What importance the question of optical activity of the lactic acid may assume is not definitely known. Just as some groups of bacteria have a specific effect on the lactose, producing only one modification of lactic acid, so bacteria attacking lactic acid may exercise a selective action and use only one or the other optically active modification. In other words, the early flora of cheese-ripening bacteria may determine the later flora by the production of a form of lactic acid attacked by one group of bacteria and not by another, and the effect on the flavor will differ accordingly. The amount of lactic acid in the cheese increases for a time, then decreases.The errors in determining lactic acid are considerable. It seems that the tendency is toward an increase of lactic acid in the cheese long after the lactose has disappeared. Two explanations are offered: one, that in the lactic acid fermentation an intermediate compound or compounds are formed which exist for some time, the conversion into lactic acid being complete at about three months; the other is that lactic acid is formed as a product of paracasein proteolysis.

The lactic acid formed in cheese ripening does not exist in a free state but reacts with the calcium salts in the cheese and forms calcium lactates. It is thought that there is sufficient of these salts to neutralize all the acid formed, and therefore the acid does not enter into combination with the paracasein salts. It has been found that lactates are the principal source of acetic and propionic acids. These are supposed to have some effect on the flavor of the cheese.

The effect of lactic acid as a determinant of bacterial and enzymic changes is very important. Early in the ripening process, lactic acid suppresses the growth of undesirable micro-organisms. It also furnishes the acid medium necessary for the best action of both the coagulating and peptic enzymes.

The importance of the lactic acid bacteria in cheese ripening has been summed up by Hastings117 as follows: "The functions of this group of bacteria in Cheddar cheese are through their by-product lactic acid as follows: (a) To favor the curdling of milk by rennet. (b) The bacteria of the milk are held in great part in the curd. Through the acid they influence the shrinkage of the curd and expulsion of the whey, (c) The acid so changes the nature of the curd as to cause 'matting,' or 'cheddaring' of the curd, (d) The acid activates the pepsin of the rennet extract, (e) The acid prevents the growth of putrefactive bacteria in the cheese. (f) It has been shown that Bacterium lactis acidi is able to form acid in the absence of the living cell. (g) The development of Bacterium lactis acidi is followed by the growth of another group of acid-forming bacteria, the Bacillus Bulgaricus group. They reach numbers comparable with those of the first group, reaching their maximum number within the first month of ripening. Since they develop after the fermentation of the milk-sugar, they must have some other source of carbon and of energy than milk-sugar." It is also probable that other groups constantly present contribute to the changes.

From the preceding discussion it is evident that each of the ripening agents has its important part to play in the ripening process and a normal ripening of the cheese is a composite result of these various agencies.

239. Conditions affecting the rate of cheese ripening.—The rate at which these agents cause ripening of the cheese depends on several factors.118 Most of these factors are within the control of man. They are as follows: the length of time; temperature of the curing-room; moisture-content of the cheese; size of the cheese; the quantity of salt used; the amount of rennet; the influence of acid.

240. The length of time.—The water-soluble nitrogen compounds increase as the cheese ages, other conditions being uniform. The rate of increase is not uniform; it is much more rapid in the early than in the succeeding stages of ripening.

241. The temperature of the curing-room.—Very few cheese factories have made any provision for regulating the temperature of the curing-room. Without such provision the temperature follows closely that of the outside air. In some cases the curing-room is located over the boiler-room and hence becomes very hot. In the cheese warehouses, provision has been made to control the temperature very closely. Experiments show that the soluble nitrogen compounds increase, on the average, closely in proportion to an increase of temperature, when the other conditions are uniform.

The temperature of the curing-room has a material effect on the quality of the cheese. Cheese made from the same day's milk, and part cured at 40° F., part at 50° F., part at 60° F. show considerable differences, the greatest seeming to be in the flavor and texture. Those kept at the low temperature cure more slowly and develop a milder flavor, those at the higher temperature cure faster and develop undesirable flavors. At the higher temperature the undesirable organisms seem to be more active. Some very skillful makers and judges of cheese have always contended that if Cheddar is properly made, firmed to the body and texture of a high-class cheese, ripening at 55 to 60° F. gives a higher quality. Such a cheese must be low in moisture, perhaps 3 to 5 per cent lower than one cured successfully by the cold process.

The following tables119 XVII, XVIII show the effect of different temperatures of curing cheese on the total score and on the points of the flavor, body and texture:

TABLE XVII

TABLE XVIII

Of the three temperatures of curing, the lowest gave a higher total score and a higher score for flavor, body and texture.

The curing temperature should not go low enough to freeze the cheese, as this lowers the quality. The cheese will cure very slowly and have a mealy texture.

242. Moisture-content of the cheese.—Other conditions being equal, there is a larger amount of water-soluble nitrogen compounds in cheese containing more moisture than in that containing less moisture. Therefore, a high moisture-content of the cheese causes it to cure faster. The presence of moisture also serves to dilute the fermentation products which otherwise would accumulate and thus check the action of the ripening agents.243. The size of the cheese.—Cheeses of large size usually cure faster than smaller ones, under the same conditions. This is due to the fact that the large cheeses lose their moisture less rapidly by evaporation and therefore after the early period of ripening have a higher water-content.

244. The amount of salt.—The relation of salt to the rate of ripening is more or less directly associated with the moisture-content of the cheese, since an increase in the amount of salt decreases the moisture. Thus, cheese containing more salt forms water-soluble nitrogen compounds more slowly than that containing less salt. The salt also has a direct effect in retarding one or more of the ripening agents.

245. The amount of rennet extract.—The use of increased amounts of rennet extract in cheese-making, other conditions being uniform, results in the production of increased quantities of soluble nitrogen compounds in a given period of time, especially such compounds as paranuclein, caseoses and peptones.

246. The influence of acid.—It is necessary that acid be present but the exact relation of varying quantities of acid to the chemical changes of the ripening process is not fully known. If too much acid is present, it imparts a sour taste to the cheese. It also causes the texture of the cheese to be mealy or sandy instead of smooth and waxy.

Conditions that may increase the rate of ripening:

1. Increase of temperature.

2. Larger amounts of rennet.

3. More moisture in the cheese.

4. Less salt.

5. Large size of the cheese.

6. Moderate amount of acid.

Conditions that may retard ripening:

1. Decrease of temperature.

2. Smaller amounts of rennet.

3. Less moisture in the cheese.

4. More salt.

5. Small size of the cheese.

6. No acid or an excess of acid.

247. Care of the cheese in the curing-room.—The cheeses need daily attention while in the curing-room (Fig. 53). They should be turned every day to prevent sticking and molding to the shelf and to secure an even evaporation of moisture. If not turned, the moisture will not evaporate evenly from all surfaces and will result in an uneven distribution in the cheese, which causes uneven curing, and usually gives the product an uneven color.

The surface of the cheese should be watched to see that the cloths stick. If they do not, the surface will crack, due to the evaporation of the moisture. If the cloths are loosened, they should be removed and the surface of the cheese greased with butter. The grease will tend to prevent the rind from cracking. If the surface of the cheese is not smooth, due to wrinkles in the bandage, or if it cracks, due to the lack of cloths, it furnishes the opportunity for insects to lay their eggs and the larvÆ to develop within the cheese. Molds also lodge and grow in such cracks.

The cheese should be kept clean while in the curing-room. This means that the hands of the person handling the cheese must be clean. The shelves should be washed with good cleaning solution and scalded with hot water whenever they become greasy or moldy.

Some means should be provided for regulating the temperature and humidity of the curing-room. In most factories this is accomplished by opening the doors and windows at night to admit the cool air and closing them in the morning to keep out the hot air. Care should be taken to keep the doors and windows closely secured. The windows should have shades to keep out the sun. If the room becomes too dry, the floor may be dampened with cold water.

The length of time in the curing-room depends on how often shipment is made to some central warehouse or to the market. This usually varies from two to six weeks.

When the surface of the cheese becomes dry and the rind is well formed, the cheese may be paraffined. It usually requires four to six days after cheeses are taken from the hoop before they are ready for this process. The object of paraffining is to prevent the escape of moisture and to keep the cheese from molding.

248. Evaporation of moisture from the cheese during ripening.—The losses due to evaporation while the cheeses are curing are a considerable item. The rate of evaporation depends on the temperature and humidity of the curing-room, the size of the cheese, the moisture-content and protection to the surface.

Table XIX120 shows the effect of size of cheese and temperature of the curing-room, on losses while curing. This table shows that the evaporation of moisture is more as the size of the cheese decreases and the temperature is increased. This is probably due to the fact that the smaller cheese has more surface to a pound than a large cheese. The evaporation increases with temperature, probably because of lowered relative humidity. The humidity can be tested with an hygrometer.

TABLE XIX

The higher the moisture-content of the cheese, usually the more rapid is the evaporation. This is due to several causes: there is more moisture to evaporate; the moisture is not so well incorporated; a moist cheese does not form so good a rind.

249.Paraffining121 consists of dipping the cheese in melted paraffin at a temperature of about 220° F. for six seconds. Fig. 54 shows an apparatus for paraffining. This leaves a very thin coat of paraffin on the cheese; at a lower temperature, a thicker coat would be left. The thicker coating is more liable to crack and peel off. If the cheese is not perfectly dry before it is treated, the paraffin will blister and crack off.Before a cheese is paraffined, the press cloth is removed and also the starched circles, if loose. After a cheese has been paraffined, if the coating is not broken, the loss due to evaporation is greatly reduced. The amount of paraffin to coat a 35-pound cheese will depend on the temperature of the paraffin and the length of time the cheese is immersed. Usually at 220° F. it requires about 0.15 A paraffiner for cheese. Fig. 54.—A paraffiner for cheese. of a pound for each 35-pound cheese. After the cheeses have been paraffined, they may be left on the curing-room shelves or boxed ready to ship.

250. Shipping.—When ready to ship, each cheese should be carefully and accurately weighed and boxed. Usually these cheeses are boxed after being paraffined. If press cloths are left on the cheese in the curing-room, they should be removed just before weighing. These cloths should not be left in a pile in the factory after being removed as they have been known to heat and sometimes cause fires. They should be washed clean and dried ready for use again. If starched circles are used, they should be left on the cheese. A scale board should be placed on each end of the cheese to prevent its sticking to the box and also to keep the box from wearing the surface of the cheese.

The box should be a trifle larger in diameter than the cheese so that the latter can be easily placed in it. The sides of the box should be the same height as the cheese.The weight of each cheese should be neatly and accurately marked on each box. Care should be exercised to keep the boxes clean.

DEFECTS IN CHEDDAR CHEESE

A great number of defects may occur in Cheddar cheese. Certain of these are due to known causes and proper remedies are definable, while neither cause nor remedy has been found for other defects. Some of the common defects and their causes and remedies are discussed under different headings of the score-card as: defects in flavor, their causes and remedies; defects in body and texture, their causes and remedies; defects in color, their causes and remedies; defects in finish and their causes and remedies.

251. Defects in flavor.—Any flavor differing from the characteristic Cheddar cheese is a defect. Certain of these defective flavors can be recognized and causes and remedies given for them, while others may be distinguished as such but no cause or remedy can be given.

252. Feedy flavors.—Flavors may be characteristic of certain feeding stuffs. Feeding strong-flavored foods, such as turnips, cabbage, decayed silage, certain weeds and sometimes rank green feed, give their peculiar flavors to both milk and cheese. Freshly drawn milk usually absorbs these odors from the air in barns filled with such foods. Certain of these materials may be fed just after milking in moderate amounts without affecting the milk drawn at the next milking. Others should not be used. Milk should not be exposed to strong volatile odors. Some of the objectionable odors may be removed by airing the curd for a longer time after milling before the salt is applied.253. Acid flavors.—A cheese with an acid flavor has a pronounced sour smell and taste. This is caused by the over-development of acid which may be due to any of the following causes: (a) receiving milk at the factory which is sour or has too high development of acid; (b) using too much starter; (c) ripening the milk too much before adding rennet; (d) not firming the curd sufficiently in the whey before removing the latter; (e) developing too much acid in the whey before it is removed; (f) retaining too much moisture in the curd.

The trouble can be reduced or eliminated by one or more of the following precautions: (a) receiving only clean, sweet milk at the cheese factory; (b) maintaining the proper relation between the moisture and acidity; (c) adding the rennet at the proper acidity; (d) using less starter; (e) adding the rennet extract so that there will be sufficient time to firm the curd before the acid has developed to such a stage that it will be necessary to draw the whey; (f) producing the proper final water-content in the newly made cheese.

254. Sweet or fruity flavors.—These are the sweet flavors characteristic of strawberry, raspberry and the like. Such flavors are very objectionable and usually increase with the age of the cheese. They appear to be caused by: (a) carrying both milk and whey in the same cans without properly cleaning them; (b) exposing milk near hog-pens where whey is fed; (c) dirty whey tanks at the cheese factory; (d) micro-organisms which get into the milk through any unclean conditions.

These troubles can be controlled: (a) if milk and whey must be carried in the same cans, the cans should be emptied immediately on arrival at the farm and thoroughly washed and scalded; (b) the whey vat at the factory should be kept clean and sweet; (c) the starter must have the proper clean flavor.

Other defects may be classed as "off flavors," "dirty flavors," "bitter flavors" and the like. These are undoubtedly due to unsanitary conditions whereby undesirable organisms get into the milk, even though the particular organism is often not determined. The flavors may be improved by the use of a clean-flavored commercial starter and by airing the curd after milling before salting. The best remedy is to remove the source of the difficulty.

255. Defects in body and texture.—The body and texture should be close. A sample rubbed between the thumb and fingers should be smooth and waxy. Any condition which causes a body and texture other than this is to be avoided.

256. Loose or open texture.—A cheese with this defect is full of irregularly shaped holes and usually soft or weak-bodied. This is serious if the cheese is to be held for some time. Moisture and fat are likely to collect in these holes and cause the cheese to deteriorate, thereby shortening its commercial life.

Several causes may bring about this condition: (a) insufficient cheddaring; (b) pressing at too high a temperature; (c) inadequate pressing; (d) development of too little acid.

The corresponding remedies are: (a) cheddar the curd until the holes are closed and the curd is solid; (b) cool the curd to 80° F. before putting to press; (c) press the curd longer, possibly twenty-four to twenty-six hours; (d) develop a little higher acid in the whey before removing the curd.

257. Dry body.—A cheese with this defect is usually firm, hard and dry, sometimes rubbery or corky. This may result from lack of moisture, fat or both, and may be due to the following causes: (a) making the cheese from partly skimmed-milk; (b) heating the curd in the whey for too long a time; (c) heating the curd too high; (d) stirring the curd too much in the whey or as the last of the whey is removed; (e) using too much salt; (f) developing of too much acid in the whey; (g) curing the cheese in too hot or too dry a curing-room; (h) not piling the curd high or fast enough in the cheddaring process.

The cause should be located and the corresponding remedy found, as follows: (a) make cheese only from whole milk; (b) draw the whey sooner; (c) firm the curd at as low temperature as possible in the whey; (d) stir the curd in the whey only enough to keep the curd particles separated but do not hand-stir it; (e) use less salt; (f) develop less acid in the whey; (g) cure the cheese in a cool moist curing-room; (h) pile the curd sooner and higher during the cheddaring process.

The number of causes which may singly or in combination produce dry cheese demands experience and technical skill that calls for the development of a high degree of judgment.

258. Gassy textured cheese.—Gassy cheese has large numbers of very small round or slightly flattened holes. When round these are called "pin-holes," and when slightly flattened "fish eye" openings. These are due to the formation of gas by the micro-organisms in the cheese. When a cheese is gassy, it usually puffs up from gas pressure as in the rising of bread. If enough gas is formed, it will cause the cheese to break or crack open. Instead of being flat on the ends, such a cheese becomes so nearly spherical as to roll from the shelf at times.The gas-producing organisms enter because of unclean conditions somewhere in the handling of the milk and the making of the cheese. Some of the common sources of gas organisms are: (a) unclean milkers; (b) dirty cows; (c) aËrating the milk in impure air, especially air from hog-pens where the whey is fed; (d) allowing the cows to wade in stagnant water or in mud or in filthy barnyards and then not thoroughly cleaning the cows before milking; (e) exposing the milk to the dust from hay and feed; (f) dirty whey tanks; (g) drawing milk and whey in the same cans without afterward thoroughly washing them; (h) unclean utensils in the factory; (i) using gassy starter; (j) ripening cheese at high temperatures.

Some of these causes are within the control of the cheese-maker after the making process is begun. Many of them are avoided only by eternal vigilance. Among the recommendations for meeting gassy curd are the following: use only milk produced under clean sanitary conditions; use a clean commercial starter.

If gas is suspected in the milk, a larger percentage of commercial starter should be used. More acid must be developed before the whey is removed. If the gas shows while cheddaring, the curd should be piled and repiled until the holes flatten out before milling.

The curd should be kept warm during the piling or cheddaring process. This may be accomplished by covering the vat and setting a pail or two of hot water in it. After milling, the curd should be stirred and aired for a considerable length of time before salting. This will aËrate the curd and allow it to cool. The cheese should then be placed in a cool curing-room. (See handling of gassy milk.)259. Acidy, pasty or soft body and texture.—A cheese with acidy body may be either hard and dry or soft and moist. It has a mealy or sandy feeling when rubbed between the fingers. The causes and remedies are the same as for cheeses with acid flavors. When rubbed between the fingers, it is pasty and sticks to the fingers. It is caused by the cheese containing too much water. (See control of moisture.)

260. Defects in color.—Any color which is not uniform is a defect. The proper color depends on the market requirement. Some markets prefer a white and others a yellow cheese; however, if the color is uniform, it is not defective.

Mottled color is a spotted or variegated marking of the cheese. Several causes may give the same general effect: (a) uneven distribution of moisture, the curd having extra moisture being lighter in color; (b) neglecting to strain the starter; (c) adding the starter after the cheese color has been added; (d) mixing the curd from different vats.

Remedies for this mottled color are: (a) to maintain a uniform assimilation of moisture (see discussion of moisture); (b) to strain the starter to break up the lumps before adding to the milk; (c) to add all of the starter before adding the cheese color; (d) not to mix curds from different vats.

Seamy color.—In "seamy" colored cheese, the outline of each piece of curd may be seen. There is usually a line where the surfaces of the curd come together. It may be caused by the pieces of curd becoming greasy or so cold that they will not cement. This may be remedied by having the curd at a temperature of 80° to 85° F. when put to press. If it is greasy, this may be removed by washing the curd in cold water.Acid color.—This is a bleached or faded color and is caused by the development of too much acid. (See acid flavor for causes and remedies, page 266.)

261. Defects in finish.—Defects of this class differ from those previously mentioned in being entirely within the control of the cheese-maker. All are due to carelessness or lack of skill in manipulation. Anything which detracts from the neat, clean, workmanlike appearance of the cheese is a defect that may interfere with the sale of an article intrinsically good. Some of the common defects are: (a) unclean surfaces or dirty cheese; (b) cracked rinds; (c) moldy surfaces; (d) uneven sizes; (e) cracked cheese; (f) wrinkled bandages; (g) uneven edges.

CHEDDAR CHEESE JUDGING

Judging of cheese is the comparison of the qualities of one product with those of another. To make this easier it is customary to reduce the qualities of the cheese to a numerical basis. This is accomplished by the use of a score-card, which recognizes certain qualities and gives to each a numerical value. Each of these score-cards gives a perfect cheese a numerical score of 100. Two score-cards are used to judge cheese, one for export and the other for home-trade product. The latter is more commonly used.

The same qualities are recognized in each score-card, but different numerical values are given them.262. Securing the sample.—The sample of cheese to be examined is best obtained by means of a cheese-trier (Fig. 55). This is a piece of steel about five or six inches long fitted with a suitable handle. It is semicircular in shape, about ½ to ¾ of an inch in diameter. The A cheese-trier. Fig. 55.—A cheese-trier. edges and end are sharpened to aid in cutting. This is inserted into the cheese and turned around and then drawn out. It removes a long cylinder of cheese, commonly called a "plug." This plug should be drawn from the top rather than from the side of the cheese, because when the bandage is cut it often splits, due to the pressure against it and so exposes the cheese.

263. How to determine quality.—As soon as the plug has been removed, it should be passed quickly under the nose to detect any volatile odors which are liable to leave the cheese quickly. Next, the compactness of the plug should be noticed and the color carefully examined. Then the outer end of the plug should be broken off and placed back in the cheese in the hole made by the trier. It should be about an inch long and pushed in so that the surface of the cheese is smooth. This prevents mold and insects entering the cheese. Usually the cheese will mold after a short time where the plug has been removed. The remainder of the plug should be saved for determining the flavor and the body and texture.

The flavor can be determined by the first odor obtained from the cheese on the trier and by mixing or crushing a piece of the plug between the thumb and fore-finger and then noting the odor. Mixing and thoroughly warming causes the odor to be much more pronounced. The cheese should seldom be tasted to determine the flavor, for when many are to be judged, they all taste alike after the first five or six. This is probably due to the cheese adhering to the teeth, tongue and other parts of the mouth, making it difficult to cleanse the mouth sufficiently. The body and texture can be determined by the appearance and the feeling of the cheese when rubbed between the thumb and fingers. The body and texture are distinct, yet they are more or less interchanged. The body refers to the cheese as a whole and the texture to the arrangement of the parts of the whole. The openness of texture or the holes can be noted when the plug is first removed. The firmness of body and smoothness of texture can be determined when the cheese is rubbed between the thumb and fingers. The color can be judged when the plug is first removed. The finish or appearance may be noted either before or after the other qualities by carefully examining the cheese.

Cheddar cheese should have a neat, clean, attractive appearance; when cut it should show a close, solid, uniformly colored interior. It should have a clear, pleasant, mild aroma and a nutty flavor. It should possess a mellow, silky, meaty texture and when rubbed between the thumb and fore-finger should be smooth and free from hard particles.

264. Causes of variations in score.—It is very seldom, if ever, that a cheese is given a perfect score, for it usually has one or more defects which may be hardly noticeable or very pronounced. The seriousness of the defect is determined by the individual tastes of the judges and the market requirements. It is customary for the judge to pick out several samples and score them in order to fix the standard and if there are several judges this serves to unify their standard. Ordinarily judges will vary because of their individual tastes, unless they begin with a uniform standard.

Certain markets require cheese with given qualities which on other markets would be considered defects. For example, the Boston market requires a very soft, pasty cheese which other markets would consider undesirable.

The cheese is constantly undergoing changes due to the ripening agents so that it may not always be scored the same. For example, a cheese may have little or no flavor and after several weeks a very considerable flavor may have developed. This is probably due to the action of the ripening agents, and therefore the second time it would be scored differently.

265. The score-card.—When judging several samples of cheese, the type of score-card on the opposite page is used for each one.

This gives the date of judging and the sample number, the judge's name and reasons for cutting the score and recommendations to avoid these troubles.