Fermenting and Pickling 101

Summary

Podcast Summary: All Of It – Episode: "Fermenting and Pickling 101"

Host: Alison Stewart
Guest: Arielle Johnson, Food Scientist, Co-founder of Noma's Fermentation Lab, and Author of A Guide to Unlocking the Art and Science of Flavor
Release Date: February 7, 2025
Duration: Approximately 28 minutes (based on transcript timestamps)

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Introduction to Fermentation

Alison Stewart opens the second hour of the episode by delving into the fascinating world of food preservation through fermentation, canning, and pickling. She describes fermentation as a "process that uses different bacteria and other microorganisms to help change the composition and flavors of food," likening it to "enlisting and nurturing your own little tiny army of sous chefs to work some magic at the molecular level" ([00:37]).

Arielle Johnson elaborates on fermentation, emphasizing its role in transforming food with microbes. She explains the basic science behind fermentation processes, such as yeast fermentation in winemaking and lactic acid bacteria in sourdough, sauerkraut, kimchi, and yogurt. Johnson highlights how these microorganisms consume sugars and produce substances like alcohol and lactic acid, which aid in preserving the food and enhancing its flavors ([02:56] - [04:12]).

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Types of Fermentation

Johnson categorizes fermentation based on the primary microorganisms involved:

• Yeast Fermentation: Used in winemaking, where yeast converts sugars into alcohol.
• Lactic Acid Fermentation: Utilized in preparing sourdough, sauerkraut, kimchi, and cultured dairy products like yogurt, where bacteria produce lactic acid.
• Acetic Acid Fermentation: Involved in vinegar production, where bacteria convert alcohol into acetic acid ([04:12] - [04:18]).

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Ensuring the Right Microorganisms

Alison Stewart poses a crucial question about relying on naturally occurring microorganisms versus introducing specific cultures. Johnson responds by explaining that traditional fermentation methods rely on naturally prevalent microbes, such as lactic acid bacteria found on vegetables and in the environment. She notes that adding salt helps favor beneficial bacteria over spoilage organisms, ensuring a successful fermentation process ([04:18] - [05:39]).

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Maintenance of Fermentations

Maintaining a fermentation requires regular feeding and care, especially for starters like sourdough. Johnson compares managing fermentation cultures to "caring for pets," where consistent feeding with flour and water keeps the microorganisms active and balanced. She provides tips on storing starters, such as refrigerating sourdough to slow down fermentation when not in use, and explains the concept of "back slopping" for simpler ferments like kefir or crème fraîche ([05:39] - [08:24]).

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Safety in Fermentation

Safety is paramount in fermentation to prevent the growth of harmful bacteria like botulism. Johnson stresses the importance of creating an acidic environment and maintaining proper salt concentrations to inhibit dangerous microbes. She advises that if a fermentation turns sour and smells off, it's generally safe, but beginners should discard any batch that develops mold or unusual odors ([20:06] - [22:44]).

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Caller Questions and Expert Advice

The episode features a series of listener call-ins, each addressing specific fermentation queries:

1. Saanich from Newark ([10:02])

   • Question: Difference between regular yogurt and Russian yogurt (yashenka), and the necessity of using nitrate salt in sausages.
   • Advice: Johnson recommends using nitrate salts as a precautionary measure when fermenting meats to prevent botulism, especially with ground meats. For yogurt, she differentiates between kefir and yogurt based on fermentation processes and suggests troubleshooting steps for unsuccessful kefir batches, such as verifying the starter's viability and adjusting starter-to-milk ratios ([10:02] - [27:28]).

2. Orla from Upstate ([12:32])

   • Question: Tips for making sourdough bread, including sourcing starter culture.
   • Advice: Johnson suggests obtaining a starter from a passionate baker or starting one at home by mixing flour and water and allowing natural fermentation. She recommends resources like Chad Robertson's and Richard Hart's baking books for guidance ([12:32] - [13:43]).

3. Patricia from Manhattan ([13:43])

   • Question: Adding two-week-old red wine to a bottle of red wine vinegar to continue fermentation.
   • Advice: Johnson explains that acetic acid bacteria require oxygen to convert alcohol to vinegar. She advises using a large glass jar with ample headspace, adding existing vinegar as a starter, and covering with a cloth to allow air exposure, facilitating the transformation over a few months ([13:47] - [14:52]).

4. Philip from Honolulu ([23:53])

   • Question: Are store-bought sauerkraut and yogurt pasteurized, and do they retain health benefits?
   • Advice: Johnson notes that it depends on the brand, with some products being unpasteurized and containing beneficial bacteria. She suggests checking labels to ensure the presence of live cultures and mentions that unpasteurized products have shorter shelf lives but offer ongoing fermentation benefits ([23:53] - [24:56]).

5. Deanna from Houston ([24:56])

   • Question: Troubleshooting failed kefir batches.
   • Advice: Johnson recommends verifying the starter's quality, possibly using a commercial kefir starter or a bottle of existing kefir. She also suggests increasing the starter ratio to help initiate fermentation and explains the differences between kefir and yogurt in terms of texture and bacterial populations ([24:56] - [27:28]).

6. Control Room ([27:12])

   • Question: Favorite fermented dessert recipes.
   • Advice: Johnson suggests incorporating miso into caramel for a delightful balance of saltiness and umami with the sweetness of caramel ([27:03] - [27:35]).

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History of Fermentation

Alison Stewart shares an anecdote from Alaska, observing indigenous practices of fermenting large vegetables during the summer. This leads to a discussion on the ancient history of fermentation. Johnson explains that fermentation predates human civilization, likely existing in early primates' diets. She emphasizes fermentation's dual role in preservation and flavor enhancement, which made it an essential practice for early human settlements ([17:47] - [20:04]).

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Final Thoughts and Conclusion

The episode wraps up with Alison Stewart thanking Arielle Johnson for her insights into the art and science of fermentation. Listeners are encouraged to engage with the topic, share their experiences, and explore the diverse applications of fermentation in cooking and preservation ([27:48] - End).

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Notable Quotes with Timestamps

• Alison Stewart ([00:37]):
  "We're going to spend the hour talking about some other things you can put a lid on. We're talking about the strategies for preserving foods, namely canning, fermenting and pickling."

• Arielle Johnson ([05:51]):
  "They're a bit more like pets. I sometimes feel like a shepherd with like a flock of sheep."

• Arielle Johnson ([07:08]):
  "Well, generally there are sort of historically developed rules of thumb."

• Arielle Johnson ([12:28]):
  "Fermenting meat is something I don't like to mess around with... use more nitrates when you're starting out."

• Arielle Johnson ([20:14]):
  "If you're a beginner with fermentation, I would recommend just throwing it out and starting over."

• Arielle Johnson ([22:51]):
  "Acetic acid bacteria, which is the only bacteria that makes vinegar, absolutely needs oxygen to ferment and to live."

• Arielle Johnson ([27:28]):
  "A little bit of miso and caramel can be delicious."

---

Conclusion

This episode of All Of It provides an extensive exploration of fermentation, offering scientific insights, practical advice, and safety tips. Through engaging discussions and real listener questions, host Alison Stewart and expert Arielle Johnson demystify the fermentation process, making it accessible for both beginners and seasoned enthusiasts. Whether you're interested in sourdough, sauerkraut, yogurt, or innovative fermented desserts, this episode serves as a comprehensive guide to embracing fermentation in your culinary endeavors.

Transcript

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[Arielle Johnson]

Listener Supported WNYC Studios.

[Alison Stewart]

This is all of it on wnyc. I'm Alison Stewart. If you missed anything this week like our what the Hack, Call in about no Buy groups or our conversation with writer Hanif Qureshi about his memoir Shattered, or our big picture conversations with Oscar nominees behind the scenes of this year's most acclaimed films. Check out our podcast feed and if you like what you hear, leave us a nice rating. Now let's get this second hour started as we put the lid on another week of great conversations. We're going to spend the hour talking about some other things you can put a lid on. We're talking about the strategies for preserving foods, namely canning, fermenting and pickling. We'll start with fermenting. It's a process that uses different bacteria and other microorganisms to help change the composition and flavors of food. Think of it as enlistment, enlisting and nurturing your own little tiny army of sous chefs to work some magic at the molecular level. The brines and acidity produced through the fermentation process can extend the shelf life of your base ingredients. Ferments are a versatile kitchen strategy that can run the gamut from condiments and toppings like sauces or miso. You can ferment starters like sourdough or a gingerbug. You can ferment veggies, keeping a bit of crunch or bring on some complex flavors. Joining me now to talk about all things fermentation is Arielle Johnson, who joined us a while back to talk about her book A Guide to Unlocking the Art and Science of Flavor. She's also got a PhD in flavor science and appropriate to this conversation is a co founder of Noma's Fermentation Lab. Hi Ariel.

[Arielle Johnson]

Hi there. Thanks for having me on.

[Alison Stewart]

So as we said, you are a co founder of Noma's Fermentation Lab. But before all that, what was your introduction to fermenting in the kitchen?

[Arielle Johnson]

Some of it was actually my grandfather. My maternal grandparents lived just outside of Scranton, Pennsylvania and he was a county extension agent. So they had a lot of like tomatoes particularly around, but he would also buy in grapes to do a little semi legal home winemaking in the basement. So I think that was my first, my first introduction to the delicious delights of fermentation.

[Alison Stewart]

It's a fairly broad, broad category to process.

[Listener]

So what are the different kinds of fermentation and what do they have in common that they can all fit into.

[Alison Stewart]

This label of fermentation?

[Arielle Johnson]

Yeah, well, so I would, you know, if you're asking a microbiologist, they might have a slightly more technical definition, but I would define fermentation for, you know, normal people as transforming food with microbes. So, you know, the wine I was talking about, that is a yeast fermentation. And so in all ferment, generally you have bacteria, yeasts, technically fungi, some of these microbes. And in, in all fermentations, they're eating something sort of as food and fuel in whatever ingredient they're in. And then they are producing a new substance or molecule. So yeast eat sugar and produce alcohol, lactic acid bacteria, which are in sourdough, lacto, fermented pickles like sauerkraut and kimchi, as well as cultured dairy like yogurt. They're eating sug and producing lactic acid. And then you have oddballs like acidic bacteria. These make vinegar. They actually eat the alcohol produced by yeasts and then transform that into acetic acid, which is the, like vinegary acid in vinegar.

[Listener]

All right, so you said fermentation relies on microorganisms to produce a chemical change, right?

[Arielle Johnson]

Yes.

[Listener]

So when it's not something that you introduce, like yeast or a probiotic capsule, how do you know you're getting the right naturally occurring micronisms, microorganisms?

[Arielle Johnson]

Well, generally there are sort of historically developed rules of thumb. So especially for lactic fermentation, this is probably the one that we do the least. Intentional inoculation. There's lactic acid bacteria all over your skin, in your guts, all over the skins of microbes. It's like very prevalent and diverse sort of naturally occurring realm of microbes. And so we know, well, we know from sort of historical tradition and now we know from chemistry and biochemistry that they are pretty tolerant to salt, whereas other spoilage microbes aren't. So you'll see a lot of vegetable fermentations like, like sauerkraut, like kimchi, rely on a certain amount of salt. So you add a bit of salt at the beginning, that kind of puts a damper on anything, possibly spoilage. E and then the lactic acid bacteria gets to work and they produce acid pretty quickly, which is sort of like a double do along with the salt, hampering the growth of any other microbes. So if you have if you're doing a lactic fermentation and it turns sour, then you're generally in good territory.

[Listener]

Since these things are alive and they need to be kept alive and they need to be nourished through this process. Do you think of them like ingredients or like some sort of pet?

[Arielle Johnson]

They're a bit more like pets. I sometimes feel like a shepherd with like a flock of sheep. You know, I can't use the grass that they are eating directly, but if I treat them well, I'll have wool to shear and knit into a sweater at the end. And in this case the grass is the sugars and the wool sweater is things like lactic acid and other delicious flavors.

[Listener]

My guest is Arielle Johnson, food scientist and co founder of noma's Fermentation Lab and the author of A Guide to Unlocking the Art and Science of Flavor. Listeners. If you have any questions or success stories or about fermentation, maybe you have some failures, I don't know, you want to give us a call 2124-3396-9221-2433 wnyc. Share your fermentation stories or any other fermenting or pickling questions you have for flavor scientist Arielle Johnson. And again, Our number is 2124-3396-9221-2433 wnyc. You can join us on the air or you can text to us at that number as well. So when you're not adding microorganisms like yeast, you're relying on things found on skins and bacteria. You're looking for good bacteria.

[Arielle Johnson]

Exactly.

[Alison Stewart]

How can I make sure I'm finding good bacteria?

[Arielle Johnson]

Well, generally, you know, the USDA gives a lot of recommendations around canning, preserving, fermentation. So they're like a naturally pretty cautious group of people. But one of the one of their microbiology experts has come out and said that he can think of no example in recorded history where someone has gotten sick from lacto fermented vegetables. So if you want to be like very, very careful relying on some of these more acidic fermentations like, like a lactic acid fermented vegetable or like a vinegar generally if you have acid and it doesn't smell like a dead animal, sorry for the but you know, the nose knows, then you're in you're generally good territory with more complex fermentations like making miso. Often you start with very pure cultures or rely on a like a home maintained culture that has, you know, sort of historically not made anyone ill. Well.

[Alison Stewart]

Let'S talk about that maintenance. Because you have to feed your fermentation. You have, sometimes they need to be burped through the process. Can you walk us through some of the maintenance that folks should expect to do if they plan on making fermentation a part of their cooking life?

[Arielle Johnson]

Yeah, well, so probably the most famous, a high maintenance fermentation starter would be a sourdough starter. You know, this, this is instead of adding dried yeast to make a 11 delicious, you know, bubbly bread, you have a basically wild ongoing culture of a mixture of yeasts and bacteria and to, to kind of keep that going and keep them all in balance. With some, you know, breaking larger components down to feed to the others and then swapping various other things. You need to keep, keep adding basically flour and water to, to a sourdough starter. There's definitely ways to kind of put it into longer term storage if you're not baking every day. Often you'll see people like bring the water right down and keep it in the fridge so that the fermentation proceeds like very, very slowly. Another, you know, simple fermentation starter, if you like creme fraiche, which is, you know, that nice, like tangy cultured cream. The easiest way to make creme fraiche is to take a small amount of existing fresh and add it to, to heavy cream. You could also use buttermilk or like a kefir starter or even yogurt sometimes will work. So in that case, if you're just, you know, eating these products regularly, we call that back slopping, taking a little bit of the, of the old, the existing fermentation that you've done and adding it to kick off the, the new one.

[Listener]

I believe we have a question for you. This is Senich, who is calling in from Newark. Hi, Saanich, thanks for calling all of it.

[Saanich]

Hi. Actually, I thought of many more questions, but I'm gonna start. Okay. So first of all, I'm making yogurt. Okay. I have, I used to, I mean, I started with like a yogurt machine, you know, a regular yogurt bacteria. Then I found something called matsoni and that doesn't require all this special, you know, preparation with milk. Just put cold milk, put masoni and it works. My question is I also sometimes make Russian yogurt called yashenka and it's made from baked milk. So the first question is, like, what's the difference? Do you know, taste is different. Many people ask me if I put more sugar in it but of course I don't. Another thing I do, I'd also do sauerkraut, my own sauerkraut. I only use cabbage, carrots and salt. But my main question, that's the one I'm call was calling about, I started to make sausages. So I buy cheap milk. I mean cheap, cheap, cheap meat. And for the sausages, some people say that I have to use nitrate salt. Some people say it doesn't, it's not required. So what's the, so the second question is what's the use for the nitrate? Do I have to use it?

[Alison Stewart]

Let's start with that one. Does he have to use nitrate salt for sausages?

[Arielle Johnson]

Yeah. So fermenting meat is something I don't like to mess around with. I mean I do do it on occasion, but it is, it is one of the cases where you do have to be careful about things like botulism, especially if you're using like a ground meat because then any kind of stuff on the outside of the meat gets to the, to the inside. So, you know, there are absolutely traditions around the world where you have aged and fermented charcuterie and meat that doesn't use nitrates. Generally nitrates are, you can think of them as an insurance policy. They act almost as like an antibiotic. They're not literally an antibiotic, but they are quite good at hampering the growth of pretty much any microbe that could, that could hurt you. So I would say unless you have a, you know, time, time proven recipe that you're very confident about that, that I would tread on the side of caution and use more nitrates when you're, when you're starting out.

[Alison Stewart]

Let's go to Orla in upstate.

[Listener]

Hi Orla, thanks so much for calling all of it.

[Orla]

Hi. Hi. My question please. What tips would you have for someone who wants to make sourdough bread for the first time, including where to obtain the starter culture. Thanks.

[Arielle Johnson]

Well, so if you have a friend that is a very passionate sourdough baker and maintains their own starter, that's the easiest place to, and lowest maintenance place to, to get a starter. But it's actually possible to start your own starter. I have a lot of baker friends who do this. They'll, you know, end up at a new bakery or they'll be doing a pop up at a restaurant and you know, a mixture of flour and water left out on the counter, you know, for a few days and fed in intervals will actually grow its own sourdough starter. There are some books I would probably go with either Chad Robertson's or Richard Hart's books about baking will definitely guide you through the sort of finer steps of creating and maintaining a sourdough starter. But it is much less mythical and difficult than some people make it out to be.

[Listener]

Let's talk to Patricia from Manhattan. Hi, Patricia.

[Orla]

Hi. I've got some leftover red wine from a dinner party, and it's about two weeks old, and I'd love to add it to my big bottle of red wine vinegar. Can I do that? Will it turn into vinegar?

[Arielle Johnson]

So the key ingredient in making vinegar, in addition to a vinegar starter, you can just actually use old vinegar for that is oxygen. A lot of fermentations don't like air. So that's why we have things like, you know, sauerkraut crocs and things like that to keep things away from air. But acetic acid bacteria, which is the, the only bacteria that makes vinegar, absolutely needs oxygen to, to, to ferment and to live. So if you wanted to kind of up your stash of red wine vinegar, I'd take a big glass jar and with, you know, quite, quite a bit of headspace, dump your leftover wine in there and add, you know, maybe, maybe 10% existing red wine vinegar. You can of that with like, a cloth napkin that's tied off, and it will basically turn itself into, into vinegar within a couple months.

[Alison Stewart]

And Dan calling in from Bed Stuy. Hi, Dan. Thanks so much for calling all of it.

[Philip]

So I had a question about keeping pickles crispy. I have a lot of cucumbers around August, and last year when I tried doing a half sour, it just got soggy after a couple of. Couple of days.

[Alison Stewart]

Soggy cucumbers. Any advice, Dariel?

[Arielle Johnson]

Well, yeah, it's, it's. It's a bit perverse that the first thing we think of when we say pickles is cucumber pickles. And cucumber pickles are some of the most finicky in terms of texture. One thing besides, you know, choosing often different varieties, smaller varieties of cucumber can, can help or, you know, varieties bred for pickling. Another thing that you can do is add a little bit of calcium in the form of. I believe they sell it as a type of pickling salt. If you can also add even, even calcium hydroxide, cal. From a, like an Asian grocery store or a Mexican store, calcium essentially acts as a glue to, to, to firm up the, the molecules called pectin, that, that hold the cells together. So if the, if the pectin is kind of firmed up and glued together. The the pickle will taste a little less mushy and yeah, generally especially on like the pickling salts packaging. It'll give you an idea of the amount to add.

[Listener]

My guest is Arielle Johnson. She is a flavor scientist. She's helping us out with fermentation. If you have any questions, success story or abject fermentation failures and you we want to hear from you. 2124-3396-9221-2433 wnyc. Our screeners are standing by to take your calls. We'll have more after a quick break.

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[Alison Stewart]

You are listening to all of it on WNYC. I'm Alison Stewart. My guest is Arielle Johnson, food scientist and co founder of noma's Fermentation Lab. She is also the author of A Guide to Unlocking the Art and Science of Flavor. Today we are talking about fermentation. Okay, So I, I was in Alaska and it was the summertime and the indigenous people there were harvesting giant vegetables. I mean like cabbage the size of like a little red wagon, huge carrots. And they were fermenting. That's all they were doing was fermenting all summer long. So it made me wonder, like, what's the history of fermentation?

[Arielle Johnson]

Yeah, well, I mean the very long term history of fermentation, a lot of biologists now think that, you know, before we were even humans, when we were like earlier primates, we were eating, you know, lacto fermented food. But in terms of fermentation as a like a presence in human culture, human cuisine, I don't know that we have evidence of like the very first fermentations. But these things goes back thousands of years definitely, you know, to the beginning of like organized settlement in a lot of these places, you'll find traces of wine or of beer, both fermented foods, and almost certainly like, a long time before that. You know, I guess there's two reasons for that. One is that fermentation is an excellent preservation method. So, you know, a jar of sauerkraut or a, you know, properly fermented leg of ham will still be, you know, delicious and whole and safe to eat many months on from when you started it. Whereas the cabbage or the raw pork leg would be absolutely, you know, a disgusting pile of mush. So it's very handy for getting through the win. Also, with a lot of fermentations, they're very easy to do. A lot of fermentations actually basically start themselves like a lactic fermentation. So going back, probably there were early humans making a choice of, like, well, I'm going to eat food that has microbes in it anyway. So let's figure out a way and keep a tradition to make the most delicious ones.

[Listener]

Let's talk about safety.

[Alison Stewart]

What parts of the process are risky.

[Listener]

In terms of introducing harmful bacteria and how, you know, if something's not safe.

[Arielle Johnson]

So, yeah, the. The sort of harmful microbes you'd want to look out for. One of them is botulism, which is probably the scariest. It is also the rarest. Most modern cases of botulism that I've seen come from, like, improperly canned meats. So. So botulism is a bacteria that comes from the soil. It is completely anaerobic, so it can't grow in the presence of oxygen, and it likes protein and dislikes salt and acid. So fermentations that produce. To produce acid and use salts are a good way to. To guard against that. On the kind of more prosaic side, you have molds. Molds like to grow on the surface of fermentations. They also, you know, on the flip side, need oxygen to grow. Molds won't grow without oxygen. So the traditional way to protect against mold growth is to use like a double lid or an airlock or basically something to protect the surface of the fermentation from mold. Generally, if you find your fermentation going moldy and, you know, you're a beginner with fermentation, I would recommend just throwing it out and starting over. If you're more experienced, you don't actually need my advice for that. So if you're one, if you're wondering, then when in doubt, throw it out. Another thing to watch out for, especially if you're doing stuff this is More like longer term dairy or meat or protein fermentations. You can get not so much a dangerous bacteria, but a conversion of amino acids into biogenic amines, the most famous of which is histamine. Histamine is what causes the sort of general allergy immunoresponse in our body and things like kind of low salt, high water cheeses or some, some other sort of protein related fermentations can create these histamines and th. Those aren't like poisonous in the same way, but they can trigger discomfort or even an allergic reaction in some people. But again, that's, that's more if you get into kind of high, higher protein fermentations like, you know, mushroom, soy sauce and things like that. And again, the, the kind of ways to protect against these things. Wash your hands, wash your equipment, remove any visible dirt from anything that you're working with and make sure that you' enough salt. Basically if it's a salted fermentation.

[Alison Stewart]

Let's talk to Eric, who's calling from the Bronx. Eric, you're on the air.

[Orla]

Hello.

[Arielle Johnson]

Can I use the pickling juice that comes with like regular pickles you get at the supermarket? Oh, to start a new fermentation? Yeah, yeah, I would say if it's a, if it's a kosher dill pickle, then yes, sometimes. So confusingly, if we're talking about pickling, some pickles are fermented, some pickles we preserve by adding vinegar. So I guess the vinegar was originally fermented, so there's technically fermentation involved. But a vinegar pickle, if you, well, if you use that brine, it can preserve something. You will not get any fermentation or flavor creation that way. So if it's a, the kind of unpasteurized kosher dill pickles that are kept in the refrigerated section, that will, yeah, can definitely help kickstart the new fermentation. But generally lactic fermentations like that are pretty good at starting themselves. But if there's like a flavor profile you particularly love, it can't hurt to back slop that in.

[Alison Stewart]

Let's talk to Philip, who's calling from Hawaii. Honolulu actually. Hi, Philip, thank you so much for calling. You're on the air.

[Philip]

Hi. I have a couple of quick questions. One is the sauerkraut and yogurt and so on that you buy in the store in container containers. Are they not already pasteurized and therefore lacking in the health benefits that you would get from fermented food.

[Arielle Johnson]

It would Depend on the brand. Many yogurts are unpasteurized, which is why they're sold under refrigeration and with, with sauerkraut. Yeah, you would have to, I would have to personally check what different brands do to give you a better answer for that. But yeah, there's definite brands that you can find that don't pasteurize. Those, of course, tend to have a slightly shorter shelf life or they will continue to transform as you store them in your fridge. But it's definitely possible to find beneficial bacteria in store bought fermentations.

[Alison Stewart]

And Deanna, who is calling us from Houston, Texas.

[Listener]

Hi, Deanna.

[Deanna]

Yeah, hello. I used to live in New York and I'm still listening to New York radio every day. So my question to your guest, I find it highly interesting topic for me because I have just started brand new trying to do caffeir. So because I learned that the caffeine has more fermentation and more good bacillus while the yogurt has more gives you more calcium. So plus when you do yogurt, I used to do that in the past. Like your former caller said, you have to have those equipment to always keep it at a certain temperature. So now I'm into kefir. I like that very much. And I tried my first batch and it didn't work very well.

[Listener]

Oh, so what can, what can she do if her kefir didn't work the first time?

[Arielle Johnson]

Yeah, I would check the starter that you're using. I'm not sure if you're using a, like commercial kefir starter or a, a bottle of existing kefir. That's also a way to, to start it off. You also might want to up the ratio. So if you're, if you're just starting out, kind of maintaining your own kefir starter. And for those who don't know what kefir is, it is a lacto fermented dairy product. It's cultured dairy, kind of similar to yogurt, except yogurt is heated while it's fermenting. So you get both slightly different lactic acid bacteria and a kind of thickening gelled texture of the proteins. And so kefir is not heated when it's fermented. So you get a much looser texture and different populations of lactic acid bacteria. Yeah. So I would, if I were troubleshooting this, either get a new starter, try out a couple of different starters and then try adding more starter at the beginning.

[Listener]

All right, we have our final question is coming from the control room. Our control room. Any favorite fermented dessert recipes?

[Arielle Johnson]

Oh, a little bit of miso and caramel can be delicious. Yeah. Yeah. So it adds some saltiness, a lot of umami, both of which go well with, with that kind of sugary, roasty flavor of caramel.

[Listener]

I tell you. Just got a big no from our next guests who are like, yeah, that sounds good.

[Arielle Johnson]

Fantastic.

[Listener]

My guest is Arielle Johnson. She's a food scientist, co founder of noma's Fermentation Lab, author of A Guide to Unlocking the Art and Science of Flavor. Thanks, Ariel.

[Arielle Johnson]

Thank you so much.

[Ira Flatow]

I'm Ira Flato, host of Science Friday. For over 30 years, our team has been reporting high quality news about science, technology and medicine and news you won't get anywhere else. And now that political news is 24 7, our audience is turning to us to know about the really important stuff in their livescancer climate change, genetic engineering, childhood diseases. Our sponsors know the value of science and health news. For more sponsorship information, visit sponsorship.wnyc.org.