Are modern malts over-modified?

Homebrew Talk

Help Support Homebrew Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ninkwood

Well-Known Member
Joined
Aug 24, 2023
Messages
218
Reaction score
124
Location
Kelowna
This is a topic that I am still working towards grasping, so I probably have a false sense of reality but wanted to explore further with this community.

I've been reading that modern malts are highly efficient at converting starches to sugars and that modern barley has been bred with relatively high amounts of enzymes present to further aid in this conversion.

I've also heard John Palmer say that approximately 90% of starches are fully converted in approximately 15-20 minutes using these modern malts.

So my question is, could this be perceived as a negative by a brewer that wants to step mash and achieve different amounts of different sugars in their end product? If conversion happens that quickly at the first step in a step mash (let's say at 150F/65c), then is there even a point in adding a second step at a higher temperature?

I know this is a complex subject and I'm over simplifying it here, but I'm wondering what others might think of this theory that brewers interested in step mashing might actually be better off without modern malts.

In my limited personal experience, I've found that single infusion mashed beers are generally boring relative the the brews that I have decocted once or twice. My theory here is that this is the best way to avoid the problem I'm outlining above. My reasoning is that the decoction process physically breaks down additional starches that the enzymes cannot access otherwise, and when added back to the mash, instantly increases the temperature of the mash and the enzymes related to that new higher temperature. In theory, this would suggest that one would actually achieve a brew that contains distinctly different sugars; those converted by the enzymes at the lower mash temperature, and then those that were only accessible after the decoction.

I'm sure I'm mostly wrong here, but the more I brew, the more I want to do decoctions. The beers I've been making that way continue to be superior and I'm trying to figure out why that might be.
 
Decoctions are a fraud

Things just aren't that precise in a mash.

I've found that single infusion mashed beers are generally boring relative the the brews that I have decocted once or twice.

Are you biasing yourself into believing that because you put more work into the decocted beer that it is "less boring"?
 
I won’t be quite as blunt, but I will say I would be highly skeptical of anyone who claimed they could tell whether or not a beer was decocted and/or step-mashed just by tasting it. (That’s not quite the same as saying the decoction doesn’t change the beer; rather, that whatever changes it makes could also be made up in the recipe.)

When you say you haven’t gotten as good results with a single infusion, have you ever tried brewing comparable batches and tasting them side-by-side?

But to try to actually answer your question, I don’t think that changing the sugar profile in the way you’re suggesting—even if that were indeed happening—could have much of an impact on the beer. Basically, there are fermentable sugars (glucose, maltose, and depending on the yeast, maltotriose or in some cases maltotetrose) and everything else. Fermentation will turn all of the fermentable sugars into ethanol, and all the nonfermentable will remain exactly as they were.

While there’s a theoretical possibility that a different glucose/maltose/etc. profile would affect yeast metabolism in a way that would result in detectable differences in the finished beer, I’ve never heard anyone suggest it. Ditto, I’ve never heard anyone claim that the composition of unfermentable dextrins could be detected by a drinker (as opposed to the total amount, which is evident in mouthfeel.)

To the extent that people think decoction matters to taste (as opposed to numerical differences in starch conversion efficiency) the general reasons given are Maillard reactions and increased oxidation.

The effects of step mashing, likewise, are going to be increased activity of the non-amylolytic enzymes. Though the utility of some of those are in question as well. (I just tried my first ferulic acid rest, but I’m not expecting too much.)

As to undermodified malt, I asked an expert (who had spent essentially his entire professional career studying malt) his opinion, and he was frankly dismissive. Derisive, even.

Though I’ll add that for people who are trying to recreate old beers for historical interest or tradition for tradition’s sake, it does make sense to use undermodified malt. It’s not easy to find, though.
 
Are you biasing yourself into believing that because you put more work into the decocted beer that it is "less boring"?
No, I don't think so. But you could be right.
I won’t be quite as blunt, but I will say I would be highly skeptical of anyone who claimed they could tell whether or not a beer was decocted and/or step-mashed just by tasting it.
I certainly wouldn't make this claim. I am however beginning to believe that for whatever reason I prefer the beer I make when I've used a decoction or two. I'm really not sure why this would be and it's probably mostly/entirely coincidence.
But to try to actually answer your question, I don’t think that changing the sugar profile in the way you’re suggesting—could have much of an impact on the beer.
I must be completely missing the plot then. What's the purpose of a step mash if not to alter the composition of sugars in the end product? Are you saying it doesn't really matter if you mash at 150F vs 170F? Or is the thing going on at these different temperatures something else entirely?
 
No, I don't think so. But you could be right.

I certainly wouldn't make this claim. I am however beginning to believe that for whatever reason I prefer the beer I make when I've used a decoction or two. I'm really not sure why this would be and it's probably mostly/entirely coincidence.

I must be completely missing the plot then. What's the purpose of a step mash if not to alter the composition of sugars in the end product? Are you saying it doesn't really matter if you mash at 150F vs 170F? Or is the thing going on at these different temperatures something else entirely?
Sorry, I wasn’t clear. How you mash—how long at what temperature—absolutely affects which starch-to-sugar enzymes are active, how much, and for how long. But for those, there are really essentially only two variables you get to control: how much of the starch in the grain is extracted, and how much of the starch is broken down into fermentable sugar vs unfermentable oligos.

But neither of those things changes the aroma or flavor of the beer. ABV and mouthfeel, yes. Anything else, probably not.

It depends on what you meant when you said your single-infusion beers were boring. If “boring” refers to attenuation, ABV, or thinness/thickness, the sugar composition created by the mash is the player. If it’s taste, though, it’s gotta be something else.

Other reasons to step mash include breaking down proteins or beta-glucans, and releasing phytic acid (to lower pH) or ferulic acid (for eventual conversion by yeast to phenols.) The steps can ease the process (better runoff) or affect body and foam. Only the ferulic acid test affects aroma, and you will find plenty of folks who will argue it’s not that important.

There’s chemistry — Maillard reactions, if limited in scope, and oxidation — that happens in a decoction. If you want an explanation for a flavor change, that’s probably where it has to be.
 
Are you saying it doesn't really matter if you mash at 150F vs 170F? Or is the thing going on at these different temperatures something else entirely?
No, it does matter.

There are some common misconceptions about enzyme action during the mash. Many seem to believe that specific enzymes are only active over a narrow temperature range. This is false. All of the enzymes are active at all temperatures from below room temp and up. The rate of enzyme action increases for all enzymes as the temperature increases, but the rates are different for the differnent enzymes. Enzyme activity only ceases when the enzymes are denatured by heat. Different enzymes do start to get denatured at different temperatures, and once you reach the temp at which denaturing starts, the rate of denaturing increases as you increase the temperature. Beta amylase and limit dextrinase start to denature at similar temperatures, which are lower than the temp at which alpha amylase starts to denature, so alpha amylase stays active longer at higher temperatures than do beta amylase or limit dextrinase.

The primary difference in sugar profiles (ratio of glucose to maltose to maltotriose to dextrine) depends on how much activity you get from the enzyme limit dextrinase, which is the only enzyme in barley malt that can hydrolyze (break) the alpha 1-6 branching bonds in amylopectin. This is the enzyme that ultimately determines the fermentability of the wort. Alpha and beta amylase both create fermentable sugars (glucose, maltose, and maltotriose.) Beta amylase creates only maltose, so a mash with a longer rest in the "beta" temp zone (below a temp where beta amylase will denature in a few minutes) will result in a mash that has more maltose relative to the amounts of glucose and maltotriose, but since they are all ferementable, I don't know if it makes a significant difference in the final beer. Alpha amylase creates both long chain dextrine and short chain fermentable sugar, depending on how long it remains active. The longer it acts the more fermentable sugar is created.

A lower temperature mash (more in the "beta rest" range) will allow more action of limit dextrinase before it gets denatured, so there will be less dextrine in the wort from such a mash vs. a mash where the limit dextrinase gets denatured before it can do much (a mash in the "alpha rest" temp range.) Fermentability is primarily determined by how much dextrine is left in the final wort.

There is another reason to step mash in addition to what @AlexKay mentions. The structure of the starch granules in the malt is not homogeneous. Amylose is a linear chain of glucose units, and amylopectin is a highly branched group of chains of glucose units. The simpler structure of amylose allows the chains to pack more tighly together than the branched chains of amylopectin. This makes gelatinization of amylopectin easier at lower temperatures, than the more densly packed amylose. Since enzymes cannot act on the stach until it has been gelatinized, you cannot get complete conversion of starch until it has been completely gelatinized. In a time limited mash, you may not get complete gelatinization of all of the starch, so it does not all get solublized. Starch does not contribute to SG until it has been hydrolyzed into soluble size molecules, which are not necessarily fermentable. If you step mash, the higher temp rest has a chance to more completely gelatinize the "stuborn" starch, which then makes it available for hydrolysis by the remaining enzymes (probably only alpha amylase by this time), which makes it soluble and increases the SG of your wort. In this way a step mash can increase your conversion efficiency vs. a single infusion mash with equal mashing times. Longer mashes at lower temp rests can also increase the conversion efficiency, if the original mash time/temp combo was not sufficient for complete conversion.

Brew on :mug:
 
Last edited:
I've found that single infusion mashed beers are generally boring relative the the brews that I have decocted once or twice.
I should have framed this far better than I did initially. Let me be clear that my personal experience on brewing in general at this stage is akin to a baby bird falling out of a tree as it learns fly. I'm by no means implying that my results say anything whatsoever about what's better or what works and what doesn't. Ultimately, I'm just wondering why decoction seems to = good and single infusion seems to = bad for me so far in my experience.

neither of those things changes the aroma or flavor of the beer. ABV and mouthfeel, yes. Anything else, probably not.
This makes sense to me for the most part, except I would think that more unfermented sugar would have a secondary effect on flavor similar to how adding refined sugar to tomato sauce changes the perception of the flavors already present. My assumption here is that we can actually perceive these slight differences in unfermented sugar as "sweet", which may be false.
If you step mash, the higher temp rest has a chance to more completely gelatinize the "stuborn" starch, which then makes it available for hydrolysis by the remaining enzymes (probably only alpha amylase by this time), which makes it soluble and increases the SG of your wort.
I think this idea of "stubborn starch" is what I was getting at here
My reasoning is that the decoction process physically breaks down additional starches that the enzymes cannot access otherwise, and when added back to the mash, instantly increases the temperature of the mash and the enzymes related to that new higher temperature.
I clearly do not have anywhere near the background knowledge on the science involved here as you folks do, but it sounds like we are saying something similar: higher temperature increases access to otherwise inaccessible sugars and by doing so allows for better efficiency and a more complex wort overall. Now whether that complexity is a positive or a negative is up for debate, dependant on the brewers ability to pull the levers in a particular way, or even just good old fashioned preference. Would you agree @doug293cz ?


The chemical explanations are wonderful, but the subjective experience of the beer, by the brewer, is more wonderful. Decoction does stuff. That affects the flavor. If it feels good, do it.
Well said! I don't want to do it for the sake of doing it, but if it improves the experience I'm going to lean into it!


Thanks for all the help y'all!
 
I clearly do not have anywhere near the background knowledge on the science involved here as you folks do, but it sounds like we are saying something similar: higher temperature increases access to otherwise inaccessible sugars and by doing so allows for better efficiency and a more complex wort overall.
It would be more accurate to say that higher temperatures may make more starch available for conversion into sugar. Whether or not you actually get more sugar by stepping the mash higher will depend on the time and temperature of the lower temp rests, whether there are any amylase enzymes left, and just how resistant to gelatinization the starch in the grain you use actually is. If you already have 100% gelatinization, and enough hydrolysis to render all of the starch soluble, then the higher temp rest will not give you any efficiency increase.

Not sure we can say that higher temps alone lead to more complex wort. Decoction leads to more complex wort due to the Maillard reactions that occur when boiling some of the mash. The products of the Maillard reaction bring additional flavor compounds to the wort.

Brew on :mug:
 
I’ve always assumed the unfermentable dextrins are not at all sweet-tasting. A little bit of digging suggests that maltotriose is slightly sweet … but for most yeast, it’s also a fermentable sugar. No info available on anything longer.
 

Latest posts

Back
Top