My friend Simona introduced me to the idea of making mother or prepared cultures for cheesemaking in small 1-cup batches. Since I'm not making cheese every week, the typical recipe for 1 quart of prepared culture was too much for me. I was never able to use it up while the culture was still robust and active. Now I'm making enough prepared culture for about two recipes of hard cheese in a 1-cup (8 oz) jam sized canning jar. Scaling down the recipe means I can scale down the amount of water I need to heat up by doing everything in a 4 qt sauce pan instead of a 8 qt stock pot.
Here is how I do it:
Sterilize your equipment by submerging a steamer basket (it insulates jars from touching the bottom of the pan) and boiling 2 jam jars with lids, stainless steel measuring spoons, & a little whisk or fork for 10 minutes. Have on hand some very clean towels, a jar lifter or tongs, and a thermometer. You’ll need a ½ pint of skim or 1% milk and about ⅛ teaspoon powdered culture (check package for recommended amounts and scale it back accordingly for the amount of milk you're using). Note: Be sure to use re-culturable cultures - direct set cultures will not perform as well.
After you've sterilized your equipment, you'll need to sterilize your milk. This is done by boiling it for 30 minutes in a water bath. To do this, fill one jar with luke warm milk and fill the other with tap water. This jar of water is going to be your tester, you will open it to test temperatures so that you don't contaminate the milk. Cover jars with lids and tighten until just snug but not super tight. Set jars in sauce pan on top of the steamer basket (I remove the legs of the basket for extra room in the pan) and cover the jars with water. Bring to a boil and boil for 30 minutes. Remove from heat and let cool. You can speed this along by s-l-o-w-l-y adding cool water to the sauce pan or a couple ice cubes. Add a few more ice cubes as the others melt away. If you take the jar with milk out of the water to cool - do the same with the water jar. Make sure the two jars are treated the same way as far as temperature is concerned.
To prevent the contamination of the milk, you will measure the temperature of the water only. It should be very close if not identical to the temperature of the sterilized milk. Once the temperature drops into range you need for inoculating with your pure freeze-dried culture, you'll open the sterilized milk and add the culture, gently mix it with your sterilized whisk or fork & close it back up. Make sure you are using sterilized measuring spoons to measure the dried culture powder and wash your hands before touching the sterilized equipment. You will ripen the inoculated milk at the temperature specified for the culture and for the specified amount of time. The culture is done when thick like yogurt. Sometimes this transformation from liquid to yogurt seems to take forever and then suddenly the culture thickens in an hour.
If you are inoculating with a mesophilic culture (Flora Danica is mesophilic) you are looking for a milk temperature of 68-72° F and you'll ripen it (or hold it at 68-72°F) for 12-16 hours. If it is thermophilic (like yogurt) you want to inoculate at about 110°F. Ripen the inoculated milk for about 6-8 hours at this temperature. Once the culture is ready, you can use it or store it. It will stay in the refrigerator for 2 weeks unused or about 3-4 days after opening and using some.
For longer term storage, 4-6 weeks, the culture can be frozen in a sterilized ice cube tray. I like to use the silicone trays. The blue tray pictured on the right creates 1-oz sized cubes. Once cubes are frozen, store in a fresh zip-lock or other very clean container. Be sure to label with the date and type of culture...it is really disappointing to grab the wrong culture or an old culture and ruin a batch of cheese. You don't need to defrost the cubes before using in your cheese recipes, just drop them in and stir. Once the cubes are melted then start timing according to your recipe directions.
Great post, Rhonda. I am sure home cheese makers will find it very useful. I will immediately add a link o my resource page :) I particularly like your idea of using a jar of water to check the temperature. When I make the cubes, I make a couple of 1/2 oz. ones too. Happy Easter!
Posted by: Simona | 04/22/2011 at 02:20 PM
Thanks Simona for the inspiration! Making prepared cultures is no longer the project it once was now that I'm using the small batch method. Happy Easter!
~R
Posted by: Rhonda | 04/22/2011 at 07:11 PM