2018 ACS BOK Domain 5: Cheesemaking

2018 ACS BOK Domain 5: Cheesemaking

These are the posts from The Cheese Study Group created by Jessica Reichert ACS CCP for our 2018 exam review:

ACS Domain 5 Day 1 Part 1

TRANSPORTING MILK

• Transportation and Storage of Milk for Cheesemaking

Milk must be moved from place A to place B (depending on the operation)

• • • When the milking parlor and cheese making facility are on the same property milking is often done geographically above the cheese making room allowing the milk to be gravity fed from the milking parlor directly into the vat or bulk tank.
    • When milk must be transported over a greater distance bulk tanks on trailers are used

• Milk Moving Equipment
  • Milk Pump- moves milk inline from the receiver pump/jar to the cheese vat during milking.
  • Milk Cans- Can be jars, cans, or other food grade receptacles. These come in many varieties.
  • Bulk Tanks on Trailers- These tanks can be refrigerated or not.  Although if the milk must travel much distance refrigeration is important.

RECEIVING MILK

• High quality milk is needed to make high quality cheese and results in high yields
  • High quality milk starts at the farm. clean , healthy, comfortable animals that are handled by conscientious milkers that utilize safe food handling procedures.
• Once milk arrives at the cheese maker it is tested for antibiotics, harmful pathogens, proteins, fats, minerals, etc. If the milk does not meet the standard the cheesemaker has set the delivery is refused.
• If milk is gathered from multiple farms a test sample is taken at each stop. If one of those samples is found to be of poor quality that farm is charged for the entire tank load since it is mixed together.

SUBSTANDARD/MISHANDLED  MILK

• Off flavors and aromas in milk can come from absorption, bacteria, chemicals, and contamination.
  • Absorption
    • Poor barn ventilation can cause barnyardy taste and smell
    • Feeding the animal too close to milking time can cause milk to taste and smell of feed.
  • Bacterial
    • Acidic sour tasting milk can be caused from the LAB in milk that isn’t stored in the proper temperature environment
    • Bitter/Unclean  taste in milk can be caused by Psychotropic Bacteria (grows at 45°) especially during extended storage. Note:There are other causes for bitterness.
    • Fruity or Fermented aroma develops as a direct result of the growth of psychotropic bacteria.
    • Malty aroma and sour taste can be the result of improperly sanitized equipment.or temperature abuse.
  • Chemical
    • Cooked – nutty aroma and sweet taste result from excessive heating during pasteurization.
    • Light Induced Oxidation- smells like cooked cabbage. UV exposure leads to the breakdown of lipids.
    • Rancid- Rancidity results from hydrolysis of fatty acids by lipase.
    • Salty- Results from cows with mastitis or late in the lactation cycle.
  • Contamination
    • Flat milk lacks the creamy aroma or full-bodied flavor and is a result of contamination of milk with water.
    • Foreign contamination is varied depending on cause. Likely causes include chemical sanitizers,detergents, medications, etc.

Links that may be useful

http://milk.procon.org/view.resource.php?resourceID=000658

ACS Domain 5 Day 1 Part 2

HANDLING OF MILK BEFORE COAGULATION

• Cheese Vat
  • Cheese Vat definition: Tub in which the curd is formed and cut or broken in cheese making.
  • Cheese Vat Types and Operations
    • Open Vats: Uncovered vat in which the entire cheese making process is controlled by hand. The cheesemaker must rely on intuition and experience to know when to proceed to the next step.
  • • Double O Style Vats: The DIMA cheese coagulation vat consists in a double-circle (“double-O”) tank with flat bottom, sloped towards the discharge, closed version. Fixed installation without necessity of tilting for emptying. A special milk inlet allows to avoid any foam forming. The machine is equipped with a heating/cooling system on the vertical cheese vat walls and on the vat bottom. Inside the coagulation cheese vat rotate two agitators in circles and in opposite directions. The cutting is simply achieved by inverting from the control panel the rotation direction of the agitators. The cutting and agitation speed can be adjusted.

• Horizontal Vats: In the 1970s a number of companies began manufacturing enclosed vertically shafted vats for making cheese.  Enclosed vats helped to eliminate some of the inconsistencies in cheesemaking that were common in open style vats. They also reduced the risk of foreign material contamination.  These style vats were also able to be automatically cleaned with a (CIP) Clean in Place system.

• Heat Treatment/Pasteurization (also covered in BOK Domain 1) : Please note that raw vs. pasteurized milk in cheese making is a controversial topic. For the purpose of CCP exam I recommend sticking to the facts of what the FSR is and the time and temp for each type of pasteurization.
  • Pasteurization is defined as partial sterilization of a substance and especially a liquid (as milk) at a temperature and for a period of exposure that destroys objectionable organisms without major chemical alteration of the substance
    • Cheeses made with unpasteurized (raw) milk cannot be sold in the US unless they have been aged for at least 60 days at a temperature no less than 35° F. Since 1949, this has been regulated by  The Food and Drug Administration with the intention of protecting consumers from potentially harmful bacteria in unpasteurized milk.

• Types of Pasteurization
  • Vat Pasteurization: the simplest and oldest method for pasteurizing milk. Milk is heated to 154.4 degrees Fahrenheit (63 degrees Celsius) in a large container and held at that temperature for 30 minutes. This process can be carried out at home on the stovetop using a large pot or, for small-scale dairies, with steam-heated kettles and fancy temperature control equipment. In batch processing, the milk has to be stirred constantly to make sure that each particle of milk is heated.
  • High-temperature short-time (HTST) pasteurization, or flash pasteurization, is the most common method these days, especially for higher volume processing. This method is faster and more energy efficient than batch pasteurization. Though the higher temperature may give the milk a slightly cooked flavor, HTST pasteurization has been used for so long that people are used to the flavor.
  • Thermization involves heating milk at temperatures of around 145–149 °F (63–65 °C) for 15 seconds. Thermization is considered unpasteurized in the US.

• Seasonal Adjustments of MIlk in the Vat
  • Milk composition changes throughout the year and throughout the animal’s lactation cycle. This change in composition can affect cheese flavor as well as yield.
  • Adding cream, protein, or other lacking components can help make the batch more standardized.
    • Many small scale cheese makers opt to not make these adjustments. A choice they say allows the terroir to show in the end product.
    • Large scale producers desiring product consistency and batch yield often add components to the vat.
    • Another option is for the cheese maker to adjust the recipe to accommodate the milk composition.

ACS Domain 5 Day 2 Part 1

• Setting The Milk ( Coagulation)

• • Prepare the milk for acid or rennet curd formation
  • Heat the milk to body temperature (90°F- 100°F)
  • Add starter cultures to the warmed milk
    • Starter Cultures are bacteria that when added to milk consumes lactose and and produces lactic acid.

• Acid Set (lactic set): Bacteria, either inherent in the milk or from the starter cultures, converts the milk lactose to lactic acid, causing coagulation without the use of rennet. These cheese develop a softer curd because the high acidity causes calcium to drain with the whey. Common acid set cheeses include cream cheese and cottage cheese.
  • Acid dissolves calcium
  • Proteins become hydrophobic and re-bond to each other end to end forming a fragile net.
• Rennet Set (low acid) : the use of rennet to coagulate milk.
  • Rennet isn’t active until acid is present
  • Protein stays intact as micelle
  • Rennet cuts protein chains at the exact same point on every protein, all become more attracted to each other and bond together. The chains change polarity, become selectively polarized and become attached to each other.
  • Rennet causes micelles to become more hydrophobic than acid set; butterfat globules are trapped inside the protein structure pull away from water more intensely, so more whey drains from the curds.

• Too much acid will denature the micelles and they won’t knit themselves into curd.
• Too much rennet could over coagulate the curd creating a too dry or too tight final texture.

• Cutting/Breaking Curds

 Increased surface area speeds syneresis to reach desired moisture level in the curd.

• • Syneresis: expulsion of whey from cheese curds
  • Large curd size makes soft cheese; small curd size means hard cheeses
• Different curd sizes make different types of cheese
  • Fresh or Bloomy Cheeses (lactic set): ladle sized curds
  • Washed Rind:Walnut size curds
  • Natural Rind: Hazelnut Curds
  • Cheddar: Pea sized
  • Alpine or Grana: Rice sized

ACS Domain 5 Day 2 Part 2

•  Concentrating Curd Solids

• Once the curds are cut and desired consistency has been reached there are many options for what happens next depending on what the end product will be.
• Curds immersed in brine: pickled (Feta and Haloumi)
• Curds are kneaded and stretched in hot water: Pulled Curd (Mozzarella and Provolone)
• Curds are washed in warm water to remove calcium and acid: Dutch Style (Edam, Gouda,Colby, and Jack)
• Curds have ripening microbes added to them: Bloomy, Washed Rind, Blue
  • Bloomy: common ripening microbes are Penicillium molds
  • Blue:  common ripening microbes are Penicillium molds
  • Washed Rind: common ripening microbes are Brevibacterium molds.
• Curds are heated to between 100°F and 130°F (38°C and 55°C) and stirred to release more whey resulting in harder cheeses.
  • Gently pressed curds:semi hard (St.Nectaire, Manchego
  • Pile, mill, press: English style (Cheddar, Gloucester, Cheshire)
  • Press firmly: Alpine (Gruyere, Comte, Beaufort)
  • • • Pressed Firmly :Grana ( Parmigiano Reggiano, Grana Padano
• Separating the curds from the whey

 Manual Methods and Tools: For small batch production spooning curds and whey  into cheesecloth or a strainer is effective.

• • • Ladling/scooping: placing curds in a strainer or mold

• • • Mechanical Methods: Open Vats with drains
  • Acidity at whey drain
    • Most of the whey is separated from the curd, which stops the acidification process, and will allow the curd to form together. Most cheese is drained in the rage of whey pH6.1-6.4 (curd pH 6.0-6.3)

• • • • Acidity level and texture at time of draining.

• • • • • High pH/Low Acidity/High Calcium Phosphate Level = Pliable Final Texture
        • Low pH/High Acidity/Low Calcium Phosphate Level = Crumbly Final Texture
• Forming A Curd Mass

 Knitting: transforms the individual curds into a single, homogenous mass.  This step transforms curds to cheese.

• • • Knitting usually happens in the cheese vats, cheese press, or in a draining hoop

Web Sites Of Interest

How Cheese is Made Part 2

http://www.pnwcheese.com/blog/2009/03/how-cheese-is-made-part-ii-from-milk-to-curd.html

Cheesemaking

http://www.cheesemaking.com/?utm_content=5720895704&utm_term=cheese%20making&utm_campaign=001.00-Cheese+Making&utm_source=Bing_Yahoo&utm_medium=cpc

ACS Domain 5 Day 3 Part 1

Adding Salt To Cheese

Salt is an essential part in making cheese. It contributes to lactic acid production, microbiological control, moisture control, rind formation, texture and flavor. The amount of salt used and the stage in the cheese making process that it is introduced play a large role in what the final product will be.

• Salt Usage
  • Dry Salting Before Pressing: Salt is mixed directly into the curds (Cheddar and Blues). Direct contact with the curds expels whey.
  • Dry Salting After Pressing: Dry salt applied to rind
    • Soft rind dry salted type cheeses (Camembert, Brie) are ripened in high humidity (95% ambient humidity) environments. The high humidity helps to keep the rind moist and prevents the formation of a tough rind. The moisture also enables the surface growth of molds, yeast, and bacteria.
    • Hard Rind dry salted cheeses (Parmigiano Reggiano) ambient humidity is relatively low (85%) to encourage expelled whey to be evaporated resulting in a dehydrated surface layer of cheese. Dry salt is reapplied over and over resulting in a thick dry rind.
  • Brine Soaked (Gouda, Edam, Havarti) Many European and Italian varieties of cheese utilize a method of salting that involves immersion of the cheese in salt brine.  In this process salt is absorbed into the cheese while whey is being expelled from the cheese. The salt which is absorbed affects the texture, flavor, and physical characteristics of the cheese.
  • Brine Preserved (Feta, Halloumi) Cheeses are immersed and kept in brine indefinitely. These cheeses will continue to absorb salt. This process prevents bacterial growth and makes the cheeses able to have a longer shelf life.
• Salt and Moisture Control
  • When curds are directly salted the salt pulls the moisture out of the curds in the form of whey.
• Salt and Rind Formation
  • The rinds thickness and density can be controlled by varying the salting or brining conditions and the humidity and temperatures during or after dry salting or brining. The resulting rind will be high in salt content  and will control microbiological activity.
• Salt and Lactic Acid Production
  • In some cheeses the addition of salt disrupts the starter cultures fermentation into lactic acid. This can prevent the pH from becoming too low during pressing. As the whey is lost due to the salting it takes with it the lactose.  If the lactose were to remain it would result in excessive lactic acid resulting in low pH and unwanted fermentations during aging.
• Salt and Texture Development
  • During early aging water in the casein matrix is absorbed by the casein resulting in a change from moist curd to a drier, softer, mellow cheese.
• Salt and Microbiological Control
  • Lower the salt content the higher the number of microorganisms that can survive inside the inside the cheese. Higher the salt content the fewer microorganisms.
• Salt and Flavor
  • Salt changes the cheese flavor. In some cheeses like Blue the salt increases the action of lipase enzymes resulting in piquant flavor and aroma.

ACS Domain 5 Day 3 Part 2

Cheese Finishing Before Aging

• Curing is the term used to describe treatments introduced for desired effects during aging.
  • Rubbing: cheeses can be rubbed with spices, coffee, honey, wines, etc, etc, etc.
  • Sprayings: In some cases the rind of the cheese is sprayed with a secondary culture that is encouraged to grow.
•           Wrapping:
• • • Leaves: Cheeses like Rogue River Blue are wrapped in leaves which impart other flavors into the cheese and allow more air exchange than some other wrappings.

• Bark: cheeses like Harbison are bound with tree bark giving the cheese a woodsy flavor and impacting the ending texture and aroma.

• Cloth/Bandaged: Some cheese like cheddar can be covered in butter or lard and wrapped with cloth or bandage. This allows for air exchange and protects the cheese from harmful pathogens.

• Wax: Applying a coating of wax is one of the most convenient ways to protect the cheese during aging and keep the cheese moisture in the desired range

Domain 5 day 4 

The following link will take you to one of the best summaries of the steps of cheesemaking I have found.

http://www.marcellathecheesemonger.com/…/cheese-101-kosikow…’s-eight-basic-steps-of-cheesemaking-step-1-setting-the-milk/

In addition to being an American Cheese Society Certified Cheese Professional, I am a Certified ServSafe Food Production Manager with certifications that also include ServSafe Certified Instructor and Proctor. I am available for cheese events, cheese program development, cheese training, food safety training and 3rd party food safety auditing. See my About Me and Resume pages for more details or call me at 360 921 9908 to discuss availability.

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