Cheese is perhaps the first food to be manufactured that is currently consumed by humans. The oldest written records have references to cheese as a food. Today, cheese is available in an almost innumerable variety of kinds, flavors and consistencies. Agriculture Handbook No. 54, Cheese Varieties and Descriptions, published by USDA (out-of-print) describes over 400 varieties and indexes over 800 names. Why? The answer is that it is made by many different races of people under widely varying conditions all over the face of the earth. And the people who eat it like the various flavors and consistencies produced.
For a better understanding of the art and sciences of cheese-making one needs to know what kind of product it is and how the manufacturing procedures developed over the years. Even though the varieties differ quite widely in composition, cheese can be characterized as a product made from milk in which the protein is coagulated and concentrated. The collection of protein is accompanied by recovery of most of the fat in the milk by its entrapment in the curd. Other constituents in milk remain in the curd or are removed with the whey depending on their solubility (fat soluble vitamins and minerals associated with protein are retained in the curd; water soluble vitamins and minerals are passed off in the whey).
For centuries, cheese making has been a farm or home industry with the individual producer using surplus milk to make small batches of cheese. Goat cheese making in the US still follows this general practice. It was, and still is to a considerable degree, an art; since the middle of the 19th century however, more and more cheese has been made in specially equipped factories with greater application of science in the manufacturing procedure. Milk from all species has been used for cheese making. Because more attention has been given to increasing the productivity of the bovine species, a large proportion of commercial cheese is now made from cow milk; the milk from the buffalo, zebu, sheep and goat is also used extensively.
There are rather significant differences in the proportions of major components (fat, protein, lactose and ash) in the milk from these various species and there are also important differences in the chemical nature of each of these components. Thus, it is to be expected that a given manufacturing procedure will produce cheese differing in flavor and consistency when made from the milk of different species. The milk may even respond to the manufacturing procedure in a different way. Much of this difference can be minimized or eliminated by adjusting or standardizing the composition of the milk from the various species to a common level before using it in cheese making. More about that later.
Just as the nature of the milk from which it is made causes variations in the characteristics of the cheese, so can modifications of the manufacturing procedure. In spite of the development of the cheese making art over centuries by many individual practitioners, certain basic processes are common to all. Even though many modifications of each may be utilized, the four basic steps in cheese making are:
1. Preparation of the cheese milk 2. Coagulation of the protein 3. Freeing coagulated protein (curd) from whey and collecting it into a defined mass. 4. Aging under controlled conditions to produce desired flavor and consistency.
In this discussion of goat cheese making, each step will be treated in some detail. In most of the material, there will be no special methodology required for making cheese from goat milk, when compared with the use of milk from other species; when special techniques are required, they will be discussed at length. For more detailed information on cheese making procedures than can be given here, refer to the book ''Cheese and Fermented Milk Foods'' by Frank V. Kosikowski, The current edition is out of print, but the new one is expected to be out in 1997.
PREPARATION OF CHEESE MILK
The cheese maker must have high quality milk to make high quality cheese. The production of high quality milk has been discussed before. In summary, milk selected for cheese making must be free of objectionable flavor, free of all foreign materials, including antibiotics, free of pathogenic organisms and contain relatively few nonpathogenic bacteria and somatic cells.
Probably the most important for a commercial cheese manufacturer is preparing milk for cheese making is the standardization for composition, that is, adjusting the fat and protein content to the desired proportion. This is of extreme importance for two major reasons: 1) it is necessary to produce cheese that is legal in composition and 2) to provide uniformity in the cheese made. Agriculture Handbook No. 51, ''Federal and State Standards for the Composition of Milk Products,'' is the most comprehensive source of information on this subject.
Those making cheese in the home for personal consumption obviously do not need to be greatly concerned about composition, but if cheese is to be sold in the market, it will have to meet some standard. So, be sure to check with your local regulatory officials before making cheese to sell.
Making sellable cheese from goat milk will pose a problem in regarding composition. The problem arises from the fact that goat milk, collected from only a few does, is more variable in fat and protein content than is cow milk. Wide variation in those components results from having most of the milk producing animals at the same stage of lactation at any given time and because mid-lactation, when fat and protein are expected to be low, usually comes in mid-summer when climatic conditions favor production of low fat, low solids milk. Experience has shown that milk may vary from mid-summer and late fall; milk solids- not-fat may vary during the same time span. Cheese made from milk differing so widely in composition will vary in a similar manner. Also, the cheese maker may experience difficulty making cheese with the low fat, low solids milk.
How can the goat cheese maker solve this problem? While any one making cheese for only personal consumption can just ignore the situation and follow personal desire, those making cheese for sale cannot. To make cheese that is uniform in composition, which is legal, to be offered for sale, two conditions must be met. Provisions must be made to test the milk (and the cheese if possible) for its fat and total solids content, and a source of concentrated goat cream and goat milk solids-not-fat must be available. The Babcock Test is the traditional analytical tool most widely used to determine fat content of milk and cheese.
Although the test is quite simple and can be performed wherever cheese is made, it does require special equipment and supplies that are somewhat expensive. Total solids content is determined by drying a weighed sample to constant weight in an oven at 212 F (100 C) and calculating the percentage of sample found in the moisture free residue. A very accurate scale must be used to weigh the residue. Sweet cream, if needed for standardization of cheese milk, can be obtained from the fluid milk. It probably will be necessary to have a centrifugal separator to produce the needed cream since gravity separation of cream in goat milk is slow and incomplete.
Such standardization may be necessary to maintain the quality of cheese when the milk solids-not-fat content of the milk decreases to less than 8 percent. In the manufacture of any specific variety of cheese, it is important to determine the ratio of fat to protein (or milk solids-not-fat) needed to meet legal standards for that cheese, then standardize the cheese milk to that ratio.
Most cheese making procedures involve controlled growth/activity of bacteria and/or enzymes in either the coagulation stage, the aging stage, or both. The necessary control may not be possible unless the cheese milk is low in bacteria counts achieved by pasteurization. Since it is possible that the milk may contain pathogenic microorganisms, it is necessary (legally required if the cheese is to be sold) that all cheese consumed when "fresh" (aged less than 60 days) be made from pasteurized milk.
Some very competent cheesemakers who can be highly selective in the milk used for cheese, use unpasteurized milk for making those varieties of cheese that must undergo prolonged aging --pathogenic organisms are supposedly destroyed in the aging process, but these is still some question if the "kill" is sufficient and complete for some of the new pathogens encountered today. Because heating milk causes some physical changes in its fat and protein components, pasteurization usually involves the least heat treatment permitted. In the cheese factory equipped with a continuous HTST pasteurizer, treatment at 161 F (71.6C) for 16 seconds is usual; in the home or small factory, pasteurization is best accomplished with a treatment of 145 F (62.7C) for 30 minutes. If volume justifies the cost, this may be done in a pasteurizer vat, but can be accomplished easily by placing the milk containing vessel (preferably a stainless steel, flat bottomed, rectangularity shaped container not exceeding 12 inches in height) in a shallow pan containing 1-2 inches of water over the heating unit. An accurate thermometer should be used. Heating and holding should be followed immediately by cooling the cheese milk to the setting temperature (the best temperature for obtaining coagulation). For most cheese varieties, utilizing the production of lactic acid by rapidly multiplying bacteria to cause or aid in protein coagulation, the setting temperature should be in the range of 72-90 F (22-32 C).
COAGULATION OF THE PROTEIN
Setting the Cheese
This term is associated with practice and procedures followed in coagulating the milk protein. The three processes most often involved are: 1) culturing the cheese milk with substantial numbers of desirable bacteria (predominantly lactic acid forming) and controlling incubation conditions, the milk protein is coagulated when sufficient lactic acid is produced - giving a titratable acidity (TA) of 0.50 - 0.55, pH of 4.6 - 4.9; (2) culturing the cheese milk with protease enzyme (rennet), incubating at favorable temperature until protein is coagulated - with very little change in TA or pH; the third procedure is a combination of one and two. In a modification of the first procedure, no bacterial culture is used; instead of producing protein coagulation by the more time consuming lactic acid formation by bacterial growth, the acid may be added directly to the milk to produce almost instantaneous coagulation.
Each of the preceding setting procedures is recommended for the manufacture of some specific variety of cheese. Most of the cheese varieties that are consumed fresh are set by an acid coagulation process; cheese varieties consumed after aging are generally made by the enzyme setting process. Specific examples of the application of these methods of setting follow. Cottage and pot cheese made from skim milk, Neufchatel made from whole milk, or cream cheese made from cream.
If only bacterial culturing is used, the setting temperature suggested is 72-80 F (22-27 C) and 8 to 16 hours is generally required to form the coagulated curd. If a combination of bacterial culturing and enzyme coagulation is used, the range in setting temperature should be 80-90F; the bacterial culture should be added and incubated for about an hour then the enzyme added. Coagulation should be completed in 4-6 hours.
Several varieties of cheese may also be made by adding an acid directly to the milk to cause almost instantaneous coagulation. Acid materials that can be used include hydrochloric acid, lactic acid (purchased as a pure concentrate or in the form of very sour whey from cultured cheese making), vinegar (acetic acid), or citrus fruit (lemon, lime) juice. If these acidulates are added to warm milk, the coagulated protein will tend to be granular or grainy and is difficult to process into a smooth, creamy cheese. If the acidulate is added to very cold milk that is then slowly warmed without stirring to setting temperature, a smoother, less grainy coagulum will usually result. Cheeses that are aged 60 days or more, such as Cheddar, Brick, mold-ripened cheeses and most Italian varieties, are generally set by the enzyme-only method, or by adding a very limited amount of bacterial culture followed by immediate addition of the enzyme material. All of these varieties of cheese, normally made in the US from cow milk, can be made from goat milk.
CURD RECOVERY AND TREATMENT
Determining just the proper time to terminate the incubation phase and begin the curd recovery phase of cheese making is probably the most difficult decision required in cheese making. While there is an optimum for each cheese variety, the desired qualities or characteristics are quite similar for all. For acid coagulated cheese, tests for titratable acidity or pH can be used to determine when coagulation has occurred. For enzyme coagulated cheese, or if the acid degree tests (TA or pH) cannot be made, other less objective tests can be made. Many experienced cheesemakers use the following test. Insert the thermometer into the coagulated milk at a 45 angle then lift the tip up through the curd and observe the way the coagulum breaks. The hole left when the thermometer is removed should fill with clear whey in a short time. It will break cleanly in a fairly straight line when the proper firmness has developed - experience is needed to determine the proper ''curd break'' for each cheese variety.
When the coagulum has attained the proper characteristics it is ready to be cut. This may be done at home with a long thin spatula or knife; commercial cheesemakers will use metal frames, sized and shaped to fit their cheese vat, having parallel fine wires spaced at regular intervals. Pairs of frames are generally used with one having the wires attached in a vertical pattern and the other in a horizontal pattern. By passing the frame with the vertical wires through the curd in the container first lengthwise then crosswise, and following that with the frame having the horizontal wires, the curd is cut into uniformly sized cubes. The size of the cubes is determined by the spacing of the wires. Uniformity in particle size is conducive to regular expulsion of whey and uniformity of cheese. Large curd particles tend to retain more moisture (whey) than small particles. The cut curd is allowed to remain undisturbed for a short time to undergo some firming due to whey expulsion.
Up to this stage, the manufacture of all cheese has been quite similar but from this point on the process is different and specific for each variety. Space does not permit a detailed description of each; a number of books, bulletins and other publications are available describing specific manufacturing procedures in detail. Those who wish to enter into the business of making and selling cheese should refer to such publications as well as confer with the proper regulatory officials. Others who desire to make cheese for personal consumption may wish to recover the coagulated protein by any simple method. Most such methods involve the application of mild heat (cooking) to help firm the curd particles and expedite whey expulsion. Heating may vary from only a few degrees above setting temperature to as high as 130 F with times varying from a few minutes to one hour or longer. Heating should be accompanied by mild stirring - sufficient to prevent the curd particles from remaining on the bottom or fusing.
When the curd particles have reached the desired firmness and whey retention, the excess whey should be removed and the curd drained. The simplest way to accomplish this is to dip, siphon or drain off (through a valve in the cheese making vessel) the free whey using some form of strainer to retain the curd particles as the liquid whey flows. In some cheese making procedures, when cooking is minimal, very little free whey can be removed, so that most of the coagulum is transferred to the curd collecting device. In all cheese making processes, final expulsion of whey and curd collection is accomplished by some special technique. These may vary from a cloth filter bag into which the high moisture curd may be ladled, to lined molds of many sizes and shapes, to allowing the curd particles to settle to the bottom of the cheese making vessel where further drainage and matting together occurs. In this process, weight or pressure may be applied to fuse the curds into a solid mass and to reduce further the moisture retained in the curd.
Variations from simple cooking, draining, and curd collecting can be used in this stage of cheese manufacture. Salt is frequently added to the curd during the final stages of draining, or the newly formed cheese block is floated in a salt brine. The addition of salt improves the flavor, texture, and keeping quality of the cheese. Cheese frequently contains one or more percentage salt.
In several procedures, after the free whey is removed, the curd is held at incubation temperature for 1/2 to 1-1/2 hours with frequent stirring, or compact in masses matted together, to promote bacterial and enzyme activity and speed up the aging process. In some instances, bacterial or enzyme concentrates may be added during this stage to produce more rapid and more controlled flavor and texture development during aging. At the completion of this stage of processing, the whey-free curd is either ready for consumption, or has been formed into regularly shaped masses suitable for storing and aging.
While each of the foregoing processes makes some contribution to the particular flavor, body and texture qualities of each variety of cheese, the manner and time of aging probably influences those qualities more than all other phases of manufacture. Those cheeses eaten while fresh obviously owe their flavor, body and texture qualities to the manner in which manufactured -including the incorporation of flavor inducing ingredients. Cottage cheese may be consumed as just the curd, but usually is found to be more palatable if a milk or cream dressing is added. Many variations of cottage cheese can be derived by the addition of fruit, vegetables, nuts and other condiments. Baker's or pot cheese is similar to cottage but is usually softer and of higher moisture content and is generally used without any added flavoring material as an ingredient in other foods such as cheesecake. Neufchatel and cream cheese, being higher in fat content, are richer tasting than cottage or Baker's, but can be flavored in the same way and are practically interchangeable as to usage.
Those varieties of cheese that are consumed after 60 or more days of aging present special problems. The purpose of aging is to develop specific flavor, body and texture qualities; these result from the growth and activity of microorganisms and enzymes. For such development to take place, the cheese must be maintained under conditions favorable to the growth and activity desired. These aging conditions can also result in objectionable changes if the original milk was contaminated with undesirable microorganisms, or if improper manufacturing procedures were used.
Aging large quantities of cheese requires special physical facilities. Sufficient space must be provided to contain more than the amount of cheese produced in a time span equal to the expected age of the cheese when ready to consume. Such space must be under strict control as to temperature and humidity. If the cheese is to be sold when 90 days old, sufficient cubic footage of space, climate controlled with shelving, for storage of the amount of cheese that is to be manufactured in 90 days must be provided. Obviously, the space will have to be reused several times annually if cheese production is continuous.
There are numerous variations in the way in which the compressed masses of cheese curd may be treated in preparation for aging. In aging cheese, those microorganisms and enzymes that were active in coagulating the protein are retained in the cheese and contribute to physical and chemical changes throughout the aging. Whether they predominate depends on what other ripening agents (bacteria, yeast, molds and/or enzymes) are added during curd collection and pressing or in the early stages of aging. Most cheese contains added salt; it may be incorporated in any phase of manufacture (several varieties of cheese are made from milk containing high levels of added salt) by adding to the curd during pressing, by soaking the formed masses of curd in brine, or by surface application of dry salt. Numerous varieties of cheese owe their characteristic flavor, body and texture qualities to the predominating activity of a single kind of agent throughout the aging period (several examples are Blue cheese) inoculated early in the aging process with Penicillium roquefortii and Brick or Limburger that gain their distinctive taste and aromas from the bacteria Brevibacterium linens.
Directions for Making Goat Cheese in the Home
Up to this point this discussion has dealt with cheese making procedures in general and their application to goat cheese. It warrants reiteration that most varieties of cheese can be made from goat milk - some adjustment of milk composition might be necessary, and aged cheeses made from goat milk would not be identical to those made from cow milk with flavor, body and texture. It is the purpose of this final section to give specific directions for making several varieties of cheese from goat milk only for home consumption with equipment and supplies usually found in the home. It is hardly worth the time to make cheese unless at least one gallon of milk is available. All cheeses should be made form pasteurized milk, unless one is aging the cheese for more than 60 days. However, aging may not always eliminate the pathogenic bacteria, so it is highly recommended to use pasteurized milk for aged cheese as well.
Cottage or Baker's Cheese
Collect surplus milk, selecting that which is free of objectionable odors; cool to and hold at 40F until used. Skim off cream; use the skim or low fat milk for cheese and the cream as cheese dressing. Better quality cheese can be made from pasteurized milk; collect all the milk to be processed in a flat bottomed straight sided vessel (rectangular shape is best) and heat to just 145F using low heat or by placing vessel in a slightly larger one containing water. Try not to exceed 145 F by too much; hold at that temperature 30 minutes, then cool at 72-80 F by circulating cold water around milk containing vessel. Use a dairy thermometer.
Inoculate cheese milk with desirable lactic acid fermenting bacterial culture. Initial source may be purchased commercial buttermilk, sour whey saved from previous cheese making (if not more than 4 days old and held at 40 F) may be used if it has clean acid taste and no gas formation has occurred. Add about 5 Inoculum (6-1/2 to 7 oz. to 1 gallon or 8 oz. to 10 lb. of milk), stir well, and set undisturbed where temperature will remain at 72-80F until firm curd is formed in 10-16 hours.
If raw milk is used for making cheese that will be aged for more than 60 days, it must be of the best possible quality and as fresh as possible. Follow the procedure outlined previously; it will be best to buy a fresh source of inoculum for each batch of cheese.
When the curd has attained the proper degree of firmness, as determined by the way it breaks when the thermometer is lifted through it, do the best possible to cut curd into uniform cubes not more than 1/2 inch in size, using a knife, spatula, or wire cutter.
Allow the curd to remain undisturbed for a few minutes, then begin to warm it very slowly, with frequent but delicate stirring. Cooking temperature should not exceed 135 F and should continue till curd has desired firmness and freedom from whey.
When the curd has the desired firmness, discontinue heating and stirring. Dip, siphon, or decant the excess whey from the top of the cheese making vessel. The curd should settle to the bottom of the container; if it floats, gas producing bacteria have been active and a new source of culture must be used for subsequent batch.
When excess whey has been removed, replace it with cold water, wash curd, and remove wash water. Wash a second time with ice water to chill curd so it will keep its fresh flavor longer.
Final drainage of the curd, using draining board or a cloth lined form with perforated sides and bottom, completes the manufacturing procedure.
The procedure is like the cottage cheese process excepting that rennet is added to hasten coagulation (see discussion of Domiati cheese making for sources and usage of rennet in cheese setting). The cooking process will be greatly shortened, and the whey separation is accomplished by transferring the curd, together with the minimum whey necessary, to a coarse mesh bag. From 4 to 16 hours may be needed to drain completely the excess whey; this should be done at refrigeration temperature if possible.
NEUFCHATEL AND CREAM CHEESE
Both are made by the procedure described for cottage cheese, excepting that richer milk or cream is used as the starting material, and whey drainage must be done in a cloth bag as little free whey is separated.
When consumed, should have the curd as separate and distinct particles and is usually dressed with a milk or cream mixture containing salt and/or other condiments.
All of these fresh cheeses may be served in a large variety of forms through the incorporation of chopped fruits, vegetables, nuts, olives, etc. Condiments should be added to give the desired flavor.
All equipment used in making cheese should be washed especially carefully to remove all milk residues; all items should be sterilized by heat or chemical (chlorine such as bleach) application before using.
This is a variety of cheese made extensively in the area around the Mediterranean Sea. It can be eaten fresh or aged for 60-90 days before consumption. Goat milk is well suited for making this variety of cheese. Domiati cheese can be made from milk that is free of objectionable flavor, should be collected as previously described. Cool the milk to 105 F and to each gallon of milk add 8 ounces of salt. This must be stirred till completely dissolved. This cheese can be made from raw milk, but pasteurization by the method previously described is recommended.
Coagulation of this cheese milk is accomplished by the addition of a protease enzyme (rennet). The enzyme may be purchased in liquid or tablet form from supply houses advertising in goat magazines, or locally from some drug stores, health food stores, or a cheese maker if available in area. If purchased in the original container, directions should be given for usage. Dilute and dissolve concentrate in water, add to cheese milk and stir for several minutes. Liquid rennet preparations are usually standardized to 1:10,000, that is 1 part rennet coagulates 10,000 parts of milk. If no directions are available, use 1 milliliter (mL) of rennet liquid diluted with 40 mL water, to each 20 lb. or 2-1/2 gallons of cheese milk. Rate of usage should be adjusted on subsequent batches to smallest amount needed to produce coagulation in no more than 30 minutes. Setting should be at 102-105 F.
When enzyme is completely dispersed, allow cheese milk to remain undisturbed till firm curd is formed. Curd firmness should be measured by lifting thermometer upward through curd mass. When desired curd firmness is attained, cut the curd into as uniformly small cubes as possible. Allow a few minutes for whey separation--this may be enhanced by very slow heating and very gentle stirring.
Within 10 to 20 minutes the clear, free whey should be separated; allow the curd to settle and remove and retain about 1/3 the volume of cheese milk set as clear salted whey. Additional free whey that can be removed can be discarded.
Transfer curd and retained whey to previously prepared cloth lined molds. These may be columnar or rectangular in shape, made of stainless steel (or wood) having perforated sides and bottom; a cover which fits inside the mold body should be used. Molds should be 7 to 10 inches in height so that a drained, compacted curd block, 3-4 inches thick, is formed when draining and pressing is completed.
Fill molds with fresh curd, fold cloth liner over the top, and allow whey drainage to continue. After curd is firm enough to permit it, weight or pressure should be applied to tops of molds. Pressing and drainage should continue for 10 to 18 hours until desired moisture content of cheese is attained. It probably will be necessary to release the pressure and rearrange cloth around cheese during the operation.
When pressing is completed and cheese is formed into a compact block of desired moisture content, remove from molds, and if necessary cut into blocks 2 to 4 inches thick. Place these blocks in plastic containers for which tight fitting lids are available. Fill the cheese container with the salted whey retained from earlier separation. The cheese should be covered with an inch of whey, and the container should be so filled that when the lid is firmly attached, almost complete exclusion of air is accomplished.
The cheese filled containers should be placed where a relatively constant temperature can be attained. The best curing temperature is 60 to 65 F; a desirable flavor, body and texture should develop in about 60 days at that temperature. Aging at higher or lower temperatures should shorten or lengthen aging times, and may encourage the development of undesirable flavors.
Another variety made from goat milk - it is made in a manner very similar to Domiati excepting that no salt is added to the milk before coagulation and aging is accomplished in 14% salt brine after the cheese cubes have been salted by holding in 23% salt brine for 24 hours.
Variations in flavor, body and texture qualities of goat cheese can be produced by following the setting and curd gathering procedures described, but modifying the aging process. Modifications might include adding enzymes or flavorings to the curd or applying enzyme, bacteria or mold cultures to the cheese surface as aging starts.
SOURCES OF SUPPLIES
New England Cheese making Supply Co. P.O. Box 85, Ashfield, MA 01330
American Supply House Box 1114, Columbia, MO 65201
Dairyland Food Laboratories, Inc. 620 Progress Ave., Waukesha, WI 53186 Marschall Dairy Ingredients Division 32 S. Proudfit St., Madison, WI 53701
Chr. Hansens Lab., Inc. 9015 W. Maple St., Milwaukee, WI 53214
Adapted from: M. Loewenstein J. F. Frank S. J. Speck; U. of Georgia, Athens