DRI-VAC (H073) YOGHURT STARTER CULTURE
H073 culture consists of specific bacteria that will “come alive” when introduced into sterilized milk at 40°C. They generally require approximately 16 hours to form a good “colony,” but the amount of time can vary.If made with full cream milk in this way it is equivalent to Greek Yoghurt.
How to make yoghurt:
- Sterilize a canning bottle by placing it in boiling water for 5 min.
- Cool the bottle and fill with 1-litre fresh full cream milk. Close the lid tightly.
- Put the bottle in a deep pot with water and heat to 90°C OR place in a microwave and heat to 90°C.
- Cool the milk to 40°C (use a thermometer sterilized in boiling water.)
- Inoculate the milk by adding the contents of the H073 starter culture packet to the milk.
- Mix thoroughly by inverting the bottle.
- Place the bottle upright somewhere where the temperature can be maintained at 40°C – 35°C for 15-24 hours. A wonderbag can be used to maintain the temperature or the bottle can be wrapped in a blanket or pillow and placed upright in a Coleman/cooler box.
- Check when the milk is thick and there is a tiny bit of whey on the top. If there is a lot of whey on the top the temperature was too high, or the incubation time was too long.
- Chill it immediately for 12 hours, then remove 2 tablespoons ( 30ml) of yoghurt with a sterile spoon and store in the fridge for no more than 3 days (or in the freezer if for a longer period).
- Use the 30ml to make the next 1 litre batch of yoghurt. You can also take out 4 tablespoons ( 60ml) to make two litres yoghurt the next time and so on.
- To freeze the yoghurt for the next batch(s), sterilize an ice tray. Measure the number of millilitres your ice tray holds with water and therefore the amount of ml’s of each ice cube. Fill the trays with the yoghurt, place in airtight plastic bags and freeze.
- The shelf life of the yoghurt for consumption is approximately 10 days.
WHAT IF SOMETHING GOES WRONG?
1) If your yoghurt won’t thicken, it could mean any (or all) of the following:
a. The temperature dropped below 35°C during the ripening period.
b. The inoculating yoghurt did not contain live bacteria.
c. The milk contained antibiotics. This happens occasionally when a dairy farm must give antibiotics to a cow. It is absorbed into the animals’ system and comes out in the milk.
d. In cleaning your utensils, a bleach or strong detergent was used and wasn’t rinsed thoroughly enough. Residual amounts of either can halt or retard bacterial action.
e. You didn’t add enough yoghurt culture. This is unlikely in your first batch because the packets of freeze-dried culture are carefully pre-measured. In your second and following batches, you may add 30ml yoghurt from your fridge or freezer supply instead of a packet of culture. However, using your own culture to make yoghurt can lead to problems. If this is the case then rather purchase the DVS cultures from Finest Kind which you add directly to the milk.
f. Also unlikely, but still possible, is that organisms hostile to lactic acid producing bacteria are present in the culture.
2) If you find bubbles in your finished product, it could mean:
a. The milk was not properly sterilized before adding culture.
b. Your equipment was not clean enough.