A science question about yeast and fermentation and bread flour... and beer

[bernardsmith]

I regularly bake bread. The loaves I bake use flour milled from unmalted (raw) grain I get from the supermarket. I add bakers yeast to the flour with some water (but no sugar) and the yeast very soon begins to produce CO2 and so is presumably fermenting the sugars it finds in the flour. And this fermentation can go on 24 hours or longer if I let it. But brewers would say that you cannot ferment grains without malting. If so, what makes bread rise?

Are there significant amounts of simple sugars in wheat or barley or rye flour? And if there are why do we need to malt grains to make beer? Is this just a matter of "efficiency" - ie I might manage to get only a 1% ABV ale without malting? But my main question is how does simple bread yeast ferment flour if the only way to allow the yeast access to the sugars in grains is through the action of enzymes released through malting?

 

[sixhotdogneck]

Enzymes in bread yeast and flour break the starches down into simple sugars. It doesn't take much simple sugar fermentation to make bread dough rise, on the other hand, it takes a significant amount of enzymes and simple sugars to make a 5% beer.

https://blogs.scientificamerican.com/guest-blog/enzymes-the-little-molecules-that-bake-bread/

Malted grain contains significantly more enzymes and refined starches than non-malted grain enabling a highly refined product (i.e. beer).

 

[bracconiere]

yes you would probably get a 1% ABV beer from fermenting raw grain....i was just reading another thread about some russian fermented bread, low ABV drink...that basically sounded like just that!i know i was getting about 1% ABV from dumping steam rice in a bucket with water and adding yeast!

 

[bernardsmith]

@bracconiere: Russian femented bread? Is that Kvass?
@sixhotdogneck: thanks - so yeast contains some of the enzymes needed to break down complex carbohydrates in the flour to simpler sugars but there is only a very limited amount of sugars the yeast can produce for them to ferment. (I wonder though could we genetically modify yeast to possess far more of the necessary enzymes so that much like as in wine making we could pitch a beer yeast and that yeast would treat grain or flour like fruit? Malting and mashing would then be completely unnecessary) But to me it is quite fascinating that yeast can nevertheless ferment grains and so it is possible that even before we learned how to malt grains to make their total sugar content accessible we might have been enjoying very low alcohol beers if the water content of the dough was high enough almost as soon as we learned to gather grasses for flour and those images from Sumeria and ancient Egypt suggesting that bread and brewing were two sides of a single coin now make more sense to me - Local indigenous yeast might have provided those baking with beer and bread at different times in the process... So thank you.

 

[bracconiere]

@bracconiere: Russian femented bread? Is that Kvass?
.

believe it was., why am i being stupid again? lol

And GMO yeast?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4924617/

Now there would be a nice refreshing homebrew! ( i think that's the right article i read years ago)

 

[dmtaylor]

Yes, kvass (Cyrillic spelling KBAC).

I have made kvass before, which is made with bread and water and yeast. It ferments just fine....... but only produces about 1 to 1.5% ABV. So yes, there are some fermentables in flour or bread.

Enzymes in a malt mash will convert a LOT more of the starch to fermentable sugars.

Here, let me find a picture....