Storage of cheese starter cultures
I have decided to give a go at home cheesemaking.
I got a nice book by Mary Karlin, which seems to explain things relatively well. Now, most recipes would call for something like 1/4 tsp of starter for a gallons milk (=3.7l milk)
So I proceeded to find some starters... and here comes the problem.
Obviously I don't intend to produce tons of cheese, and the smallest packaging I've found is freeze-dried sachets of ~10g, which most vendors say is good for 100 to 300l milk!
Some websites tell you to dilute the whole pack into 1l milk, then aliquot it and freeze it for storage. Is this a viable option (the microbiologist in me says a big yes)? Or would I be better at taking a little bit of freeze-dried product everytime (hmmmm)?
Any suggestion would be appreciated.
Best Answer
I was told by a cheese merchant who sold me the culture and rennet, to store the culture in the freezer, and the rennet in the fridge.
I hadn't used it in more than two years and it's still alive and working. (as tested a few weeks ago)
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Quick Answer about "Storage of cheese starter cultures"
Specialty Cheese cultures should always be stored in the freezer. The colder you can store it, the longer it will last! All our cultures are freeze-dried which means that the environment inside the packet is perfect for freezing without any negative impact.How do you store cheese starter culture?
Cultures, molds and yeasts are packaged in a moisture barrier sealed foil packets, keeping them free from air and humidity. After opening, fold over packet a few times and place in one, if not two small plastic bags or Zip-Lock type bags. Store dry cultures, molds, yeasts and dry rennet powder/tablets in the freezer.How do you store starter cultures?
Starter cultures should arrive at your plant hard frozen and packed with excess dry ice, usually at a temperature of -78.5\xb0C (-108.4\xb0F). Prior to shipment, these cultures were most likely frozen in liquid nitrogen at -210\xb0C (-346\xb0F) and stored in freezers at -85\xb0C (-122\xb0F) until shipped.How do you store cheese cultures?
Cultures, molds, aromas and lipase powders will keep best in your freezer. Unopened, cultures will retain activity for up to two years. Once you open them, however, be sure to close them up well and also place the packet inside a sealable plastic bag or small mason jar to try to keep moisture away from the culture.How long does cheese culture last?
The milk substrate the cultures are propagated on contains no growth hormones (RBGH). If kept frozen, cultures will last up to two years. At room temperature, they will last up to two months.Cheese Culture Storage and Dosing
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Answer 2
Mary Karlin addresses this in "Artisan Cheese Making at Home" -- it sounds like you have this book.
Her recommended method is to divide the pack of dry culture into smaller doses, using a precision scale. You can store these in small ziplock bags, in a bigger ziplock bag, in the freezer.
Your starter came freeze-dried. That process made it both cold and dry. The overall idea is to keep the bacteria dormant by keeping them at low temperature and maintaining that low humidity environment. No repacking will be as good as the original package, but it's best to open it once, weigh and repackage into individual doses; instead of opening the original package each time you make cheese.
As @rumtscho mentioned, you can get limited range, high-precision (0.01 gram) scales pretty cheaply. You can also buy tiny ziplock bags that work well for this.
You may want to find this section in Mary Karlin's book -- there are some pictures. I'll look it up when I get home.
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