Troubleshooting

Troubleshooting

My yogurt is runny -- what is going on?

Possibilities:

  1. Have you made homemade yogurt before? Homemade yogurt usually has a thinner consistency than the yogurt sold in stores because it contains none of the stabilizers or thickeners that are often added to the store-bought variety
  2. You may want to try a different yogurt culture – ABY2C is our yogurt culture that generally produces the thickest-bodied yogurt.
  3. Did you heat your milk to 180°F and hold it there for 30 minutes before cooling the milk to 108-115°F and then stirring in your culture? Heating the milk to 180° for 30 minutes affects the proteins in milk in such a way (known as denaturing) that it results in a thicker product.
  4. Did you add enough culture? In a related matter, did you shake up your culture before pouring out what you needed to get a good mixture of the different bacteria strains?
  5. Did you incubate your yogurt long enough, and at the correct temperature? Make sure your thermometer is calibrated correctly and that you are following the temperature guidelines for yogurt-making. Note that if you are using raw (unpasteurized) and/or goat or sheep milk, you will need to add 2-4 hours to the recommended incubation time for your culture.
  6. Tried all the above and still not getting a thick enough product? Some people like to add powdered milk or unflavored gelatin to make a thicker yogurt. Add 1/3 cup powdered milk for every quart of milk before heating the milk. Otherwise, you may want to try straining your yogurt with a draining bag or cheesecloth for a few hours after the incubation period (drain in refrigerator).

I'm trying to make cheese and it's not forming a curd.

Possibilities:

  1. Check that your milk is at the recommended temperature for the kind of cheese you are making and be sure your thermometer is calibrated correctly.
  2. Using the same amount of rennet for different milk types can affect your coagulation; for example, between 1% fat and full fat, or between cow, goat, and sheep's milk, or even between different cow or goat species there can be differences that require subtle changes in the amount of rennet used.
  3. Low casein (protein) content of the milk will cause problems in coagulation. Use different milk or add skim milk powder before adding rennet.
  4. Old milk – if you are using non-pasteurized milk, bacteria can increase during the time between milking and cheese making, which will impact your milk’s ability to curd.
  5. Severity of heat treatment during pasteurization will have an impact -- Ultra Pasteurized milk is difficult to coagulate, and Ultra-High Pasteurized milk may not coagulate at all. Use milk that has not been ultra-pasteurized.
  6. Starter culture inhibition due to mastitic and late-lactation milk, higher free fatty acid levels, antibiotic residues.
  7. Low calcium level in milk -- calcium levels reduce at end of lactation season. More common in pasteurized milk, the common solution is to add diluted Calcium Chloride.
  8. When you diluted the calcium chloride and/or coagulant, did you use chlorine-free water? Most city tap water contains chlorine and this can cause problems with coagulation. Use distilled water if you suspect your tap water has chlorine in it.

I'm getting some coagulation, but not enough.

Possibilities:

  1. Don't over-agitate (stir for more than a minute or so) rennet in milk for longer than recommended time, as it breaks up curds as they start to form.
  2. Incorrect amount of rennet -- rennet amounts, either liquid, paste, powder or tablet, should be measured very accurately: Too little rennet can result in a) slow, mostly acid coagulation rather than rennet coagulation, b) very soft curd that will shatter when cut, and c) poor flavor development during aging. Too much rennet can result in a) unusually rapid coagulation and too-firm rubbery curd that when cut will tear, b) a curd that will retain too much whey, and c) develop a bitter taste during agingPoor/improper dilution of rennet -- using chlorinated water (most city tap water) for dilution before adding to milk will inhibit curd formation. Chlorine is a strong oxidizing agent and rapidly destroys the rennet enzymes. We recommend using cool, non-chlorinated bottled or distilled water to pre-dilute rennet. Also, waiting too long between pre-diluting rennet in cool non-chlorinated water and adding it to milk will affect coagulation, as rennet enzymes become unstable when diluted and lose strength. Add your diluted rennet to the milk immediately after dilution. If using dry-powdered or tablet rennet, be sure that the dry rennet is fully dissolved in cool, non-chlorinated water before adding it to the milk. Check the pH of your dilution water if you are having coagulation problems -- low alkalinity (above neutral 7.0 pH) will result in inactivity of the rennet. Causes of low alkaline water are a) naturally alkaline water, b) pre-dilution container having traces of detergent or sanitizer, c) pre-diluting container was used for diluting colorants such as annatto, which can inactivate rennet.
  3. Coagulant/rennet strength is degraded due to improper storage or excessive age. Keep your liquid coagulant refrigerated and discard after 9-12 months from purchase.

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