Inspired by Sailor's fine pictorial essay on mother cultures
and all the great comments I made a run of 4 cultures (2 mesos and 2 thermos) and decided that MCs were the way to go. I did make some adjustments as in a good week I may make 10 lbs. of cheese so I decided to cut the amount in half (one quart per culture) using sterilized glass canning jars. That did ok but with the double-boiler set-up it was awkward and demanded a lot of attention to temperature control.
Thinking about how to make the process simpler for the small-scale cheese maker I came up with the system described below. It doesn't require much equipment and you can use milk from a gallon jug to reduce costs:
1. Equipment: Two heavy-duty (3 mil) 1-qt ziplock bags; 1 qt. measuring cup; perforated plastic tray to hold bags; crock pot and thermometer.
2. Setting bags in measuring cup helps when filling.
3. Bags go into tray or small colander that fits into crock pot.
4 & 5. Heat to 200 deg. F and hold for 30 min.
6. You can use the hot water to sterilize trays.
These were mesos (MM100 and MA4002) so all I had left to do was to cool the bags to room temp and wait for it to thicken (took about 14 hr.) and pour into the trays.
The crock pot took about 3 hrs. to heat the water so next time I'll determine how much water is needed, heat it to boiling in a stock pot
and pour into the crock pot and add the bags, using the pot to maintain temperature above 200F. The slowness of the crockpot to heat is an advantage when sterilization temperature is reached, as there is little risk of exceeding boiling temperature. Also, as crocks heat around the sides rather than from the bottom it eliminates hot-spots.