The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Beer yeast

Kuret's picture
Kuret

Beer yeast

I am thinking about purchasing some whole malt from a brewers supply, but since they employ "single rate" shipping ie. no matter how much you order the shipping and handling costs stays the same I am thinking, can beer yeast be used directly in bread? Or will this result in odd taste or over rising?

Mike Avery's picture
Mike Avery

I had the same idea a long time ago.  I used lees from lager beer to try to raise bread.  It didn't work at all well   24 hours later, there was no sign of rising.

Ale yeast would have been a better choice as it works faster and is the same species as bread yeast.  Lager yeast is sacrhomyces carlsberginses, ale is sacrhromyces cervisa.  (Sorry about the spelling errors there.)

 

Historically, the English used barm (taken from actively fermenting beer) to raise bread.  While it worked, it's significant that few people still do that. Since then there has been lots of careful selection done with brewing and baking yeasts.

 

Beer, or ale, yeast is a different strain from bread yeast and beer and ale yeast are really not optimal for bread.  Beer and ale yeast work better in a more liquid environment where bread yeast is happy in a more solid environment.

 

Mike

 

foolishpoolish's picture
foolishpoolish

 

(edit: oops just realised I have pretty much just repeated the above information re: top fermenting ale yeasts)

 

foolishpoolish's picture
foolishpoolish

I was under the impression that the enzymes responsible for amylase (hydrolysis of the starch portion of the flour) exist in the flour itself. The amylase enzymes are activated when the flour is hydrated. Yes they can be bolstered by addition of diastatic malt or indeed sprouting grains etc.

However I don't know that yeast is 'diastatic' at all.  Yeast produce both invertase and maltase to metabolize complex sugars  such as maltose which are the product of the natural amylase process that occurs when flour is hydrated. The yeast break these down into simpler sugars (glucose, fructose) which they can then use.  I wasn't aware that they are capable of breaking down 'raw' starch glucose chains.

AFAIK diastatic malt is used in brewing but only in the mashing stage to produce the wort.  I don't think it's used in the fermentation stage when the brewing yeast is added...it wouldn't make much sense to add it once you already have all the sugars you need?

Brewer's yeast of the lager variety is a bottom fermenting yeast which typically works at low temperatures...it's possible the environmental factors rather than the enzymes are the reasons for it's unsuitability in bread making? 

I could be way off mark here... 

 

 

 

 

mrpeabody's picture
mrpeabody

Many years ago, I used to brew my own beer.  I'm not sure whether flour has much diastatic activity (or much of the amylase enzyme).  There might be low levels of it but not so much to make alot of conversion from starch to simpler sugars.

You have to remember that grains are seeds and that the whole point of the big stores of starch is that they serve as stored food for the germinating and growing embryo.  With respect to barley, this meant that the enzymes for chopping up the long strands of starch to the simpler sugars that the sprout can feed on do not really get expressed until the embryo is growing (evidenced by sprouting).  To make beer, the barley grains must be encouraged to sprout  to upregulate the diastatic enzymes.  The germinated barley is then carefully dried so that the enzymes are not deactivated.  Thus, when the resultant malted barley gets crushed and mixed with water, the released active enzymes can have a party on the long strands of starch and release the simple sugars (that the yeast will need to feed on).

I don't believe that wheat is germinated before grinding into flour, so I would not suspect that much diastatic activity exists in normal flour.

Most barley malt that is bought as either a syrup or as a powder has been processed such that the diastatic activity has been inactivated.  However, there are versions of malt (either as syrup or powder) that has been specially processed so that the enzymes are not inactivated and that these malt products are marked as diastatic.

Mr. Peabody

foolishpoolish's picture
foolishpoolish

How then can one explain the conversion of starch to sugar in bread baking? This is the problem I've been trying to get my head around.

Apparently, yeast do produce some amylase but my understanding is that again this is not in significant proportions to make fermentation happen as quickly as it does.  

Does this mean that all the flours one typically buys have some malt/enzyme additive?  

OR 

Does the instant yeast one buys contain enzyme additives...or perhaps some sort of nutrient (sugars?) to kick start the yeast to reproduce in enough numbers to begin breaking down starches?

How does pain a l'ancienne work if the whole premise is to delay (by temperature) the activity of the yeast to achieve better flavour?  Is there some other agent at work in that instance? It's confusing! 

 

mrpeabody's picture
mrpeabody

Well, I'm not a microbiologist, but we can make some educated guesses and perhaps it is a mix of explanations.

The description that I gave about malted barley and beer is, from my recollection, fairly accurate.  However, you'll note that the major difference is relative quantities of starch to be converted into simpler sugars.  For beer-making, you want as much starch turned to simple sugar in order to turn as much of the barley into potential food for the yeast to eat and then burp CO2 gas and alcohol (along with a wide cocktail of aromatic esters that impact flavor).  Oh...and also heat.  For breadmaking, getting that much starch converted to sugar would be inadvisable (you'd just get alcoholic goo).  It probably is harder anyways because the dough is a relatively low proportion of water to grain stuff for bread compared to the mash that is used to convert barley malt to wort (the sweet liquid for the yeast to dine on).

But...there probably is some low level conversion.  The question is to the source of this conversion.  Possibilities are yeast (my guess is probably very little if at all, and this is a pure guess), flour (maybe, but because wheat flour is not malted before grinding, it would be very small), or other action by other microbes (in the flours or water).

Enzyme rates are affected by many factors.  Temperature is a biggie as lower temperatures overall slows enzyme action.  Of course, the optimal temperature range for any particular enzyme can differ from each other, so perhaps, lower temperature affects some more than others.

One thing that temperature does greatly affect (an this is from my beer making days) is the by products of fermentation from the yeasts.  Higher temperatures in beer fermenting produce more fruity esters (so the ales fermented at warmer temperatures are different in character compared to the same yeast fermented slower at cooler temperatures).  Maybe the profile of the yeast by products produced in retarded doughs differ enough to be perceptible?

Final possibility is that the lower temperature retards different microbes (yeasts and bacteria) in the dough at different rates so that some microbes, maybe some lesser population of bacteria are less retarded than the yeast and thus produce some other "flavors."  I sort of like this one as the many sourdough people here do report that overnight proofing in the refrigerator allows different flavors to come to the fore.  It may be more of time as the retarding at cold temperatures of the yeast (to slow the proofing time, may give the other "beasties" time to add their flavors to the dough/bread).  The sourdough starters are a complex mix of "beasties."

But I'm just guessing.  I'm sure there are other factors.  I'm just musing off the top of my head.

 

Mr. Peabody

Kuret's picture
Kuret

Looking at this discussion it seems that I can conclude that buying yeast intended for ale or lager fermentation is not a good idea for bread baking, whould seem quite pointless to as I am currently using about 30g of yeast a year not counting the weight of the yeast micorobes in my starter.

The malt however, is it safe to assume that it is diastatic if it is in whole grain form? I understand that the "easy road to brewing" spray malt and other similar products like brewers sugar doesnt cut it with them having little to no active enzymes. Maybe making my own malt whould be a better idea as I might be able to source some barley from a local farmer..

foolishpoolish's picture
foolishpoolish

Sorry Kuret. I didn't mean to confuse the subject. It's just an area that I've also been thinking about recently. 

I think ale yeast *will* work - but I would avoid lager yeast. That said, it would be safer to stick to baker's yeast or use a natural leaven (sourdough starter) - something which I know works within the environmental conditions and ingredients that are involved in making bread.

As for the malt - don't worry -  If it says 'diastatic' then it should do the job.  

Although at the risk of complicating things further -  I know that some brewer's diastatic malt is graded according to it's diastatic power...the more powerful, the stronger the enzymatic effect.  No idea what 'power' would be suitable for baking purposes though...I asked the same question a few weeks ago in another thread.  I doubt you need to add a lot of malt - you don't need the high sugar yield that one associates with mashing. 

Kuret's picture
Kuret

The grading according to diastatic activity do not seem to be a common one here in sweden rather grading according to how roasted the barley has been. Like caramel malt or lager malt wich is lighter in color etc.