Category: fermented food

Homemade Yogurt: What I’ve Learned

Seth Roberts18 Comments

Years ago I made yogurt using a recipe from Saul Sternberg. I still use the same ingredients — the basic point is to add about 1/2 cup powdered milk per quart of regular milk at the start — but I implement the temperature changes differently. Since I became interested in fermented foods, I’ve made yogurt a dozen times. Here’s what I’ve learned.

1. Makes a great condiment. I blogged about this. Store-bought yogurt, even the plain stuff, is too runny — not thick enough — nor sour enough to make this clear. The addition of powdered milk makes the yogurt thick enough to easily eat with anything, including meat. It improves the flavor of just about anything, especially if the yogurt is really sour. This might be the most important lesson since it means you can eat it at every meal and it makes cooking easier. I use spices much less now. The yogurt supplies complexity.

2. You can incubate it for days. I want it as strong as possible — not only because more sour (food writers euphemistically say tart) is better but also because the longer it ferments the more bacteria there will be. After a while it stops getting more sour and I stop. I routinely let it incubate one or two days, much longer than any recipe I’ve seen.

3. Preheating helps. Most recipes say you should heat the milk before you add the cultures. Some say this kills “bad” bacteria, which could compete with the bacteria you add. According to Harold McGee, the preheating denatures the milk proteins, which helps them trap liquid (whey). I did a little experiment in which I didn’t preheat some of the batches. Without preheating, the yogurt was much less solid. Supporting McGee.

4. Strauss yogurt better than Pavel yogurt. (Two popular Bay Area brands.) When I make a new batch I start it with store-bought yogurt; that works better than using what I have left. Side-by-side tasting showed that Strauss yogurt is more sour than Pavel yogurt. I made yogurt using each as the starter; the Strauss-started yogurt was clearly more sour than the Pavel-started yogurt.

5. Slow cooker works great. It is very easy to do the preheating via a crockpot (also called a slow cooker). I put it on high and wait 3-4 hours. This heats the milk to about 185 degrees F. Then I cool it down, add the cultures, and put the whole crockpot in the oven (set very low) to keep it warm for a few days. No spillage. I use a food thermometer to track the temperature. I got the idea from the Shangri-La Diet Forums.

6. Whole milk better than low-fat milk. Whole tasted better.

Harold McGee’s recommendations.

Homemade Kombucha: What I’ve Learned (part 2)

Seth Roberts11 Comments

I’ve been making it in 2-quart jars. Doing little experiments, I’ve figured out that

1. 4 tea bags is better than 6. I’ve been using Tetley’s low-cost black tea. Each teabag supposedly has 33% more tea than usual. In Wild Fermentation, Sandor Katz suggests 4 teabags for 2 quarts.

2. 3/4 cup of sugar is better than 1/2 cup of sugar. The Wild Fermentation recipe says 1/2 cup of sugar for 2 quarts.

Part 1.

Bay Area Fermentation

Seth Roberts3 Comments

Yesterday’s San Francisco Chronicle had an article on fermented foods in the Bay Area: the fermentation festival, sauerkraut, kimchi, and so on. (No discussion of yogurt.) I especially liked this:

Leaving foods unrefrigerated for two weeks or more can be disturbing to those who weren’t raised with a crock of pickles in the hallway. But U.S. Department of Agriculture research service microbiologist Fred Breidt says properly fermented vegetables are actually safer than raw vegetables, which might have been exposed to pathogens like E. coli on the farm.

“With fermented products there is no safety concern. I can flat-out say that. The reason is the lactic acid bacteria that carry out the fermentation are the world’s best killers of other bacteria,” says Breidt, who works at a lab at North Carolina State University, Raleigh, where scientists have been studying fermented and other pickled foods since the 1930s.

Breidt adds that fermented vegetables, for which there are no documented cases of food-borne illness, are safer for novices to make than canned vegetables. Pressurized canning creates an anaerobic environment that increases the risk of deadly botulism, particularly with low-acid foods.

Nothing about fermented — also called aged – meat. The last taboo. I believe we like umami flavor so that we will eat more bacteria-laden protein. (Glutamate, which produces the umami flavor, is a protein breakdown product.) All meat producers, as far as I know, age their product 2-3 weeks to improve the flavor. Understandably, they don’t like to talk about it.

Thanks to Ashish Mukharji.

Homemade Kombucha: What I’ve Learned (part 1)

Seth Roberts7 Comments

From Rejuvenation Company‘s kombucha I learned how good it can be. From a Ferment Change party a few months ago I got kombucha starter. Now I have eight jars brewing kombucha. Here’s what I’ve learned:

1. Hard to fail. It’s hard to kill the kombucha “mother”. After weeks in an airtight bottle (see Mistake 2), after I let air in it grew fine. You make kombucha at room temperature. You don’t have to check it. You simply wait until it’s sour enough.

2. Air needed. It’s aerobic fermentation, so it needs unlimited oxygen. I learned this after I used a sealed container and nothing happened.

3. Takes weeks. It has taken weeks for my kombucha to become really sour. Maybe I can reduce this to a week under better conditions (high surface to volume ratio, start with large kombucha mother).

4. Use a wide container. The more surface to volume, the better. The kombucha culture grows on top of the tea/sugar mixture because it needs contact with air. The wider the container, the more contact it can have.

5. Cover tightly with something air-permeable. I cover each jar with a paper towel secured with a rubber band. Before I started using a rubber band to hold down the paper towel I found a fly in one of them.

I use cheap black tea (in teabags) and ordinary sugar. Maybe I should get a pH meter to learn more about the process.

More Benefits of Fermented Foods

Seth Roberts6 Comments

A study published last year in Oncology Reports found that fermented noni (an Asian fruit) juice fights cancer in rats.

Noni (Morinda citrifolia) has been used in traditional Polynesian folk medicine for more than 2,000 years. Recently, researchers have discovered that Noni juice has the ability to destroy cancerous tumors. . . .

The researchers evaluated Noni’s ability to both prevent and treat cancer. In the prevention study, female mice were injected with one of three substances: fNE, a phosphate-balanced solution (PBS, which is similar to saline solution), or lipopolysaccharides (LPS, a natural toxin found in bacteria and in fermented Noni juice) for three days. Then the researchers injected the mice with lung cancer and sarcoma cells. In the treatment study, the mice were first injected with the cancer cells, and then treated with three doses of fNE [fermented noni exudate], LPS [lipopolysaccharides], or PBS [phosphate balance solution].

A fter the mice were injected with fNE, they developed greater numbers of immune cells such as granulocytes (a type of white blood cell) and natural killer (NK) cells, indicating that fNE had stimulated their immune system. A month after receiving fNE for sarcoma treatment or prevention, more than 85 percent of the mice were not only alive, but also cancer-free. fNE also was effective against lung cancer tumor cells, although the tumor prevention rate was slightly lower (62 percent). Meanwhile, all of the mice that received PBS or LPS died.

Emphasis added. It is telling that they used fermented noni juice rather than plain noni juice; apparently plain noni juice is less effective. Fermented juice has many more bacteria than plain juice; it makes a lot of sense that the fermented bacteria stimulate the immune system.

Thanks to Peter Spero.

A Book About the Value of Fermented Foods

Seth Roberts1 Comment

Handbook of fermented functional foods, second edition, 2008.

Presenting new findings and interpretations that point even more clearly to the important role fermented foods play in our diet and overall health, this second edition demonstrates the current knowledge of fermented food production and reflects the growing credibility of probiotics in health maintenance.

You can read a lot of it online.

Yogurt Power

Seth Roberts12 Comments

My interest in fermented food started in January, at the Fancy Food Show in San Francisco, where I had a theoretical idea: The pleasure we get from sour, umami, and complex flavors had the effect, when it evolved, of increasing bacteria intake. This suggests we need to consume plenty of bacteria to be healthy. Three things happened at that convention that supported these ideas: (a) Someone trying to make a high-end non-alcoholic drink said he found it impossible to get enough complexity without fermentation. (b) I remembered that after a trip to Japan, I had started eating lots of miso soup. Miso (fermented soy beans) is an unusually effective flavoring agent. (c) A Stonyfield Farms employee told me that her health improved a lot when she started eating yogurt every day two years ago. (Stonyfield Farms makes yogurt.)

Recently I learned more about the health improvement. She started eating more yogurt about two years ago because she changed jobs — from an architecture firm in Boston to Stonyfield, in New Hampshire, where the employee kitchen has a refrigerator full of free yogurt. In Boston, she ate yogurt about once/week; at Stonyfield, she eats it once/day (for breakfast).

When she moved to New Hampshire, she also changed her diet in other ways. She now eats more foods that are “natural and organic” and less fast food. She doesn’t eat anything with aspartame any more; she also avoids caffeine. She eats more fruits and vegetables. Maybe the biggest change is that she eats three good meals every day instead of one meal on the run. Other changes in her life include less stress, a different atmosphere, and more exposure to nature.

In Boston, she had lots of colds and sinus infections, maybe 3-4/year. When she got sick it took a long time — 2 weeks — to get better. She also felt sick to her stomach a lot. In Boston she got mononucleosis; it took six months to completely recover. In New Hampshire, she’s had only 1 cold in the past year and it only lasted 3-4 days. No other illnesses. Another change she’s happy about is that she gained weight. In Boston she weighed about 90 pounds; now she weighs about 110. (She’s 5′ 4″ and 30 years old.)

She’s noticed that Stonyfield employees are healthier than other places she’s worked (as this study suggests). Fewer people are sick and when they’re sick they aren’t sick as long. Everyone eats the free yogurt, except the lactose-intolerant. Stonyfield yogurt contains less than half the lactose of milk; for some lactose-intolerant people that’s low enough, for others it isn’t low enough. (Stonyfield makes a soy yogurt without lactose.)

Can Probiotics Prevent Asthma?

Seth Roberts2 Comments

From a UCSF press release:

In the first effort of its kind in the United States, researchers at the University of California, San Francisco have launched a study to determine whether giving active probiotic supplements to infants can delay or prevent asthma in children.

The intervention is a novel method for the primary prevention of asthma with enormous potential to have a public health impact, said Michael Cabana, MD, chief of the Department of General Pediatrics at UCSF Children’s Hospital and principal investigator for the study. There currently are no known ways to prevent asthma, he said.

“It would be a great thing to be able to prevent asthma,” Cabana said. “We believe that using probiotics is a safe and effective way to do that.”

The press release is from May 2006; the three-year study should be almost finished.

Thanks to Steve Hansen.

Kimchi Power?

Seth Roberts9 Comments

From a Korean father’s recent email to his daughter:

It is reported that the [swine] flu is spreading in Queens area, except for the Korean-American concentrated area. The reason is that kimchi bacteria kills swine flu bacteria. Kimchi is now very popular in China. Please have [Grandchild 1] and [Grandchild 2] eat kimchi.

Can anyone reading this tell me if swine flu is less of a problem in the Korean part of Queens than in other parts?

I hope so. I eat kimchi every meal and use the big glass bottles it comes in to make kombucha. Kimchi is indeed popular in my section of Beijing but I thought it was because of the Korean students. There are so many the neighborhood is called Koreatown. There is even a North Korean restaurant! Beijing is close to Korea — which is good, because I love Korean food.

Thanks to Paul Sas.