The Yogurt Diaries
October 1, 2008
The ineffable Maria and I like yogurt smoothies for our daily breakfast. And we like to make them with organic yogurt, but organic yogurt is be expensive. So I’m re-learning how to make yogurt, partly so we can economically indulge in our daily smoothies, partly to see what variations in texture / tanginess we like.
Last night I made the first experimental batch. Here are the lab notes:
Yogurt Batch 081001 [A,B,C,D]
- Wash 4 one quart (~1 liter) wide mouth canning jars in the dishwasher with heated drying. This does a reasonable job of sterilizing the jars.
- Fill each jar with three cups (0.7 liters) of organic low-fat (1%) milk.
- Immerse in water bath (in this case, in a slow cooker), heat water bath to 110F (43.3C)
- Once the bath has reached the target temperature, stir in 4 tablespoons (0.06 liters) of live-culture yogurt purchased at the local supermarket. In this case, we used Mountain High All Natural Plain yogurt containing L.Bulfaricus, S, Thermophilus, L Acidophilus, B Bifidus and L Casei.
- Mix well! It required a surprising amount of stirring to get the yogurt broken up and distributed though the milk.
- Wrap the jars and water bath in an insulating blanket and incubate. The incubation times for each sample:
- Sample 081001 A: 3h40m
- Sample 081001 B: 5h00m
- Sample 081001 C: 6h20m
- Sample 081001 D: 7h40m
- Put sample in refrigerator to stop incubation process
Notes
- Note that in traditional recipes, one heats the milk to 180F (82C) and then cools it to 110F (43.3C) before adding the yogurt cultures. This is to kill any other critters in the milk. I skipped this step, relying on the freshness of the milk and the cleanliness of the jars. If I’m patient enough, I’ll include this step in a future batch to see if it makes a difference, but it does take time.
- I used a modified 50W aquarium heater to maintain the temperature of the water bath, and measured it with a cooking thermometer. The heater worked very well, and temperature variations appeared to be less than +/- 1 degree F.
Results
All four samples had a thin layer of curd floating on top which was textured and slightly thicker in consistency than the rest of the yogurt.
- Sample 081001 A: (3h40m) — Much too runny. Flavor was fine, but it was really like thick milk with a yogurt taste. Should work fine in a smoothie or over granola, though.
- Sample 081001 B: (5h00m) — Good. Thin texture, but firm enough to hold up in a spoon. Light flavor.
- Sample 081001 C: (6h20m) — Very good. Firmer texture, slightly tangy flavor but still very delicate compared to the mother culture.
- Sample 081001 D: (7h40m) — Very good. The top layer of curd was somewhat thicker, and I could convince myself that the flavor was tangier than 081001 C. As a pragmatic point, it’s not clear that the extra 1h20m incubation time makes a real difference.
Commentary
Since a gallon (128 oz) of organic milk costs $6 at Safeway, and a quart (32 oz) of organic yogurt costs $4, we’ve essentially reduced our cost from $0.125 per ounce to $0.047. Assuming we use the yogurt from a previous batch as the culture mother for the next, a quart of yogurt that used to cost $4 now costs $1.50.
I liked the results, especially Sample 081001 C (6h20m incubation). Shorter incubation produced a thinner texture, longer incubation didn’t appear to make much of a difference. Skipping the lengthy “heat to 180 and cool back down” step didn’t seem to hurt the results, but might be worth trying. Ideas for future batches:
- get an insulated cooler for incubation. it will leak less heat, and I will be able to incubate six quart jars at a time.
- use “russian style” yogurt as a culture.
- use goat’s milk
- use skim milk
- use water as a base and add powdered milk. (do they make organic powdered milk? is it less expensive?)
October 20, 2008 at 3:54 pm
sample D was definitely the best.
when is the next post about the goat yogurt piece?
October 20, 2008 at 4:04 pm
There is a little about goat milk yogurt in:
http://blog.robertpoor.com/2008/10/18/
and soon there will be more on that very topic.
November 3, 2008 at 1:54 pm
I’ve got my first batch going right now, in a water bath in the slow cooker, which seems to be maintaining an even 100 degree temperature. I also used a sterilzed quart jar and milk from the fresh container, that had been brought to room temperature.
Organic Valley dried milk IS available, even at my neighborhood market, and at only $2.99 for 1.5 gallons’ worth, on sale.
November 3, 2008 at 2:18 pm
Heather:
(I’m pleased and slightly surprised someone else is reading this thread!) I bought a packet of Organic Valley dried milk and tried it out in a subsequent batch.
If you skip ahead to http://blog.robertpoor.com/2008/10/18/, you’ll see my notes on the making of it. I’ve been slacking and still need to post my comments about the results of that latest batch. All I can say is check back (soon) for those comments.
Congratulations on becoming a kindred yogurt maker!
But a question for you: many recipes call for bringing the milk up to 180 degrees, then cooling back down to 100-110 before culturing. Did you do that? What are your thoughts on same?
Best,
- Rob
P.S.: “Yogurt Makers do it with culture.” …I don’t believe I said that!
April 23, 2009 at 8:15 am
Hi Robert, Thank you for your posting. Can you tell me how did you modify the aquarium heater, to get it up to the right temperature? Out of the box they mostly go to 94F max, to avoid cooking the fish. Thanks!
April 23, 2009 at 8:50 am
Hi Kevin:
I bought an “Aqueon” TA50 50-watt aquarium heater. On the top is the temperature adjustment knob which only goes up to 88 F.
But here’s the thing: on this model, the knob has a mechanical stop that prevents it from making more than one revolution. If you pull the knob off, you’re able to turn the central shaft more than one revolution, and thus, turn it higher than 88 degrees. (For the electronically minded, there’s a ten-turn potentiometer inside — with the knob in place, it’s limited to a single turn.)
I put it in a jar of water with a digital thermometer and, with a little trial and error, I was able to set it to 110 degrees. Works like a champ.
- Rob
[PS: You should NEVER cook your fish. As we all know, sushi is much better!
]
August 9, 2009 at 1:23 am
Robert, thank you for the tip about aquarium thermostats! I want to make large amounts of yogurt in single batches using a large glass bottle in my crock pot but its lowest temperature is about 150F. [I have been using Yogourmet 1/2 gal. incubator.] I DO heat milk to 180F, first. I incubate for 29 hr. to remove ALL lactose (sugar) for digestive reasons.
I use the non-CBA Yogourmet starter which contains ONLY L.acidophilus, L.bulgaricus, and S.thermophilus and NOT any Bifidus or unspecified “other” cultures — again, for digestive reasons (as described in the Specific Carbohydrate Diet (SCD)).
I wonder if I could find a 5 gallon jug for an enormous batch of yogurt! :-O
August 11, 2009 at 7:20 pm
Joan:
I’ve already learned so much from you! For example, I didn’t know that a long incubation time would remove all lactose — that’s important!
Can you give me a pointer to the Yogourmet starter? Can you purchase it on line?
As a practical matter, you *could* make the yogurt in six one gallon wide-mouth Ball jars, such as in:
http://theconsumerlink.com/FreshPreserving/detail/TCL+68100/101
That might be more practical than a single 5 gallon batch. At 9.5″ tall, the jars would just (perfectly) fit into the cooler I use.
- Rob