Osmotolerant Yeast

I don’t have a picture of this because I don’t have any and you have to special order it in bulk. What, you think I’m made of money? This is a highly specialized form of instant yeast, actually a different yeast species called Pichia sorbitophila. It was discovered in 1980 infecting a container full of 70% sorbitol, a sugar alcohol. That’s a heck of an unfriendly environment for any small critter, and when it was discovered that sorbitophila produced as much CO2 as other fermenting yeast species (Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Debaryomyces hansenii) a product was born.

Most yeast species can’t withstand the osmotic pressures exerted by high levels of salt and/or sugar. Sorbitophila can, which makes it great for very sweet or salty doughs. I’ve owned it and liked it, however I ultimately decided the extra expense wasn’t worth it to me. If you’re a pro, or just someone obsessed with making the world’s most perfect monkey bread, this is for you. However you can get a very similar effect using instant yeast, simply by increasing the amount by 25% when the sugar content gets over 5% of your dough weight.

24 thoughts on “Osmotolerant Yeast”

  1. I was taught that salt kills yeast and sugar makes it reproduce more/faster, or something to that effect? Would this yeast just be less reactive to salt and sugar? So you can make it rise even with contact with sugar and salt?

    Thanks for all the yeast posts, by the way. I don’t use yeast very often, and I’m still learning about it 😛

    1. Hey Nick!

      That’s quite right, though yeast thrive when there’s some salt around, as long as it isn’t too much. They can tolerate more sugar, though not terribly much before it starts to bind up water, depriving yeast of water they need to grow and reproduce.

      And thanks! These have been fun!

      – Joe

      1. Thanks for the reply! I never knew that about the sugar and salt. I always wondered why we even used salt with yeasted things, and why I couldn’t use more sugar. Now it makes sense.

  2. How is osmotolerant yeast different than the Gold label SAF yeast that makes the claim that it will ferment in reduced amounts of water when sugar monopolizes the largest part of the water in a given recipe?

    SAF Gold is affordable enough at around $6-7 for a 16 oz package. Admittedly, most of us will end up chucking half of 16 oz eventually but it’s still very available. At least online.

    1. Hey Rainey!

      SAF Gold is osmotolerant yeast, the very same thing. And yes, being able to thrive in low-moisture environments is indeed its super power. Both salt and sugar are known for depriving and/or robbing microbes of the water they need to thrive. Osmotolerant yeast is able to carry on in the face of all that resistance…up to a point anyway.

      Glad to hear the price has come down…not sure it’s worth it to me since I did indeed end up throwing most of mine out after a year or so. But I would never discourage anyone from trying it out!

      – Joe

      1. I’ve done a little reading. It also claims to be much more effective with really sour sourdoughs.

        I keep my yeast in the freezer it airtight jars and use it as long as it’s still proofing. As I said in another part of this yeast discussion I’m still working from one of those 16 oz. packages that’s at least 18 months past is expiration date. I think it may be time to chuck it and get a fresh supply but I think the companies that package yeast are very conservative about their dates. A good policy, I think, for making products that are reliable for consumers but also reason to push the envelope on my end. ;>

        1. I bought a 2-pound pack of dried (regular) yeast about 3 years ago at Sam’s Club, and it’s still alive and kicking (through 3 moves at that!) and I’ve just kept it in a ziploc baggie in the fridge. No idea what the brand was as I tossed the original packaging, but it seems to be pretty hearty stuff.

          1. Hey Melanie!

            Active dry is the most resilient of the various packaged yeasts when it comes to resisting cold, so that doesn’t surprise me too much. The instant yeasts don’t hold up as well…a year at best.

            – Joe

  3. King Arthur Flour has SAF Gold yeast that they refer to as “special” for sweet breads. Is this the same thing, or different?

    1. You can probably order it if you really want some…there must be a commercial supplier that can acquire it. Do you have Sysco down under? They can get anything.

      – Joe

        1. I don’t blame you. Keep up the search as I bet it’s out there somewhere!

          – Joe

        2. Chris-

          I will have a fresh supply very shortly and I’d be more than happy to send you some in exchange for a self-addressed envelope. That way at least you could experiment and decide if it’s something you want to go to the trouble and expense of ordering from outside Oz.

          The issue is exchanging addresses. Unfortunately I don’t do Facebook so I can’t respond directly to you. If you want to e-mail me at IamRainey@gmail etc I bet we can work something out.

  4. So the for sweet dough yeast that I had never actually seen before I moved here (or noticed more like it) is probably that. hmmm. neat. The yeasts cost the same so.

    1. Yes, I’ll bet that’s it. And indeed they do cost the same. I can see why the Scandinavians would be into that, since they love sweet, fluffy breads. Give it a try and report back if you can!

      – Joe

      1. I’ve already tried it, but I wasn’t sure it helped. Was rather unsure how it would matter. I could always send you some if you like. 🙂

        ….I wonder if thats somehow against the border laws?

        1. Ha! Probably. But I’ve used it and had a similar doubt: did it help that much? I should have done some back-to-back tests, but then I’m lazy!

          Have a great weekend!

          – Joe

  5. We use SAF Gold in our brioche dough, although fresh yeast works nearly as well. Although our brioche dough is very wet, it is also very sweet and the yeast always seems to have a tough time fighting the sugar for water.

    We dissolve the yeast in the water before adding anything else. Giving the yeast first crack at a good drink also seems to help.


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