fermentable sugars in my sourdough bread

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hey.ryanm

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Hey y’all!
Not sure if I should post this in the fermentation/yeast section or the mash section. Sorry if this is the wrong place.
I have a question about fermentable sugars in my sourdough bread to use in a single grain (sourdough bread) brew.

I’m gonna try my hand at a Kvass basically. All recipes call for added sugar which seems to be strictly for the yeast and not flavor. I’m trying to find information on what kind of fermentable sugars I can get just out of the bread. Looks like people pour boiling water over the bread and let soak for 24 hours- which would be considered the mash? (Sorry new to home brewing and experimental brewing makes it even trickier for my brain to grasp lol).

I can also bring it to certain temps for certain amounts of time like a standard mash but not really seeing any information for that regarding a bread mash without any other grains.
maybe follow directions for like an all wheat mash?

as of right now, I am planning to do the 24hr soak but nothing is set in stone.

okay so, to ferment the “kvass” I will be using my sourdough starter.
I understand, I think, that when I ferment the dough the yeast is turning those starches into sugars by enzymes.

Are there just not enough sugars left for my yeast to ferment in the wort by the time the dough has been fermented and baked? Would I say, get more a better gravity of fermentable sugars if I purposely under-fermented the bread I use in the kvass? would that result in sugars left over that I can mash for my yeast to eat in primary?
I also will be toasting and caramelizing the bread in the oven, which seems to be another way to grab the breads sugars. But is this only to add sweetness?
Sorry, I’m all new to this.

Goal is to not add any extra sugar to the wort. Not sure why this is a “goal” for me but it would be nice to get by without, if I can and focus on grabbing those sugars in the bread.
I’m not too worried about ABV but I do want to ferment this to it’s full potential and dry hop it. I know most people just consume the kvass within a couple days of fermentation, when its only like 1% abv. Going the whole way until fermentation is fully complete, I would really love it 3.5-5%ABV range.

Here’s my basic plan for the brew:
I’ll use 2 Loaves of my Sourdough Bread (Flour, Water, Salt - no added oils or anything)
The grain mix is 80% Bread Flour and 20% Whole Wheat. They're both Hard Red American Wheat.

I’m doing a gallon batch but pre-boil will be 1.7 gallons will be initially brought to a boil and then poured over the bread and left covered, soaking for 24hrs

Next day I’ll strain and boil the wort for 90 minutes, cool down, and add it to my fermenter with 100g of my sourdough yeast slurry and just let it ferment until it’s done.
then I’m gonna dry hop it with some low aa German hop pellets, just .05oz.

I’m hoping my sourdough starter won’t have trouble fermenting since it’s working with all the same stuff at the same temperature it’s already used to: just a little more hydrated.

So I guess my question is how can I get the most fermentable sugars out of my bread?
And is it possible by purposely under fermenting my bread will help with having more for the yeast to eat in the primary fermentation.

Ok sorry for being confusing and rambling. Any information is great! Thanks!
 
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I've done a variation of the AHA's Kvass recipe using 2 loaves of homemade rye bread. But, I mash it with malted grains. Here's my thoughts: your plan to soak the bread in hot water won't do anything to convert the starch in the bread to sugar. Yeast feed on sugar, not starch. So, I'd add some malted grains, or enzyme, if you choose to go that route.
By the way- just noticed this is your 1st post. Welcome to the forum! :mug:
 
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hey.ryanm

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I've done a variation of the AHA's Kvass recipe using 2 loaves of homemade rye bread. But, I mash it with malted grains. Here's my thoughts: your plan to soak the bread in hot water won't do anything to convert the starch in the bread to sugar. Yeast feed on sugar, not starch. So, I'd add some malted grains, or enzyme, if you choose to go that route.
By the way- just noticed this is your 1st post. Welcome to the forum! :mug:
Hey!
Thanks for the reply, I've been a long time reader, stoked to be finally posting!
It's so hard to find info on mashing bread and what kind of fermentable sugars I can get out of it as non raw wheat. I wonder if by boiling and soaking the bread I am extracting the starch which using my sourdough starter as the yeast is converting the starches into sugars to ferment, just like it does with fermenting the dough?
 
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I believe the problem, is that when we make bread, either with plain yeast, or with a mixed sourdough starter, we are not fermenting the dough. The yeast converts the small amount of sugar present into CO2(and a very little alcohol). You need to provide enzymes from malt to convert the starch if you want to get anything significant.
Now- I do bake bread (including sourdough like everyone else this year when yeast was rare in the store). Also have brewed for 9 years, and have and studied quite a few books on brewing. But, I could be wrong about the mix of yeast and bacteria in a sourdough starter. Maybe it can convert starch to sugar, but I doubt it. There's a subsection of the forum that focuses on bread baking. I think I'll go poke around there.
 
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Call me obsessed. I did the next best thing- looked up sourdough on Wikipedia. Surprise- wheat flour contains some amylase. But not a lot which is why malted grains are preferable for beer. Lactobacillus also can ferment starch into sugar a bit. A bit. Not enough for a decent amount of sugar to produce a decent amount of alcohol. And of course baking the bread would destroy any enzymes.
So, to my mind, unless sourdough gurus (or maybe Kvass gurus) respond, if this were me, I'd mash my bread with a pound or two of malted barley or malted wheat to make sure I get enough sugars. Then ferment with my sourdough starter. Good luck, and keep us informed of your results.
 
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hey.ryanm

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Call me obsessed. I did the next best thing- looked up sourdough on Wikipedia. Surprise- wheat flour contains some amylase. But not a lot which is why malted grains are preferable for beer. Lactobacillus also can ferment starch into sugar a bit. A bit. Not enough for a decent amount of sugar to produce a decent amount of alcohol. And of course baking the bread would destroy any enzymes.
So, to my mind, unless sourdough gurus (or maybe Kvass gurus) respond, if this were me, I'd mash my bread with a pound or two of malted barley or malted wheat to make sure I get enough sugars. Then ferment with my sourdough starter. Good luck, and keep us informed of your results.
awesome you got obsessed as well haha! i've been trying to dig into as well- but i easily get lost in all of it. i think adding fermentable sugar on top of the bread is the safe bet. should start the brew this week and I'll keep everyone updated!
 
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