BIAB mash profile

[Gusmedic]

While prepping for my first BIAB and watched videos to setup my mash profile. I've read pretty exclusively about people mashing for 60min at ~154, but I was surprised to learn about the mash temp and length and how it affects the beers body. Following the guidelines, my first beer should be medium body. Meaning I should be mashing lower temp for longer. Do many people do this?

 

[stpug]

Everyone does differently. The simple single-infusion mash is fine for those beers that benefit from it, while a stepped mash is fine for those beers that benefit from it. As long as you're fully converting those starches to sugars then you're on the right track.

 

[LLBeanJ]

Yes and no. To say "I want a medium-bodied beer, therefore I should mash @ 152 instead of 154" may be correct, but it also may not be.

Mash temp is relative and, all things being equal, a higher mash temp will result in a higher FG and more body than the same grain bill mashed at a lower temp. However, all things are not usually equal and grain bill and yeast selection will ultimately determine the mash temp needed to reach a desired FG (and fullness, or lack thereof, of body). If you use BeerSmith or one of the other brewing calculators, you can play around with the grain bill, yeast selection, and mash temps to create a combo that will yield the desired FG.

As far as whether many people do this, I would assume that most experienced brewers who actively manipulate their recipes do, in fact do this (I know I do). Those who are lesser experienced or brewing kits and following the instructions likely do not.

 

[SlitheryDee]

I just listened to the latest brulosophy podcast, which coincidentally was about some xBmts they did on mash temperature. Thier findings were that two beers brewed at radically different mash temperatures were practically indistinguishable from each other in terms of body, mouthfeel, and flavor. They did differ significantly in alcohol content though.

My takeaway from that is that mash temperature does definitely make a difference in the sugar composition of the wort, but it doesn't seem to make much difference in terms of the subjective experience of the final product. Their "low mash temp" beer finished .009 lower in gravity than their "high mash temp" beer, which meant that there was a definite difference between the two, not the least of which a full percentage point in alcohol content. The only problem was that people couldn't tell the two beers apart in triangle tests.

It almost makes me believe that manipulating mash temps might only really be good for changing the alcohol content of a beer without significantly altering it's flavor characteristics.

 

[rhys333]

I just listened to the latest brulosophy podcast, which coincidentally was about some xBmts they did on mash temperature. Thier findings were that two beers brewed at radically different mash temperatures were practically indistinguishable from each other in terms of body, mouthfeel, and flavor. They did differ significantly in alcohol content though.

My takeaway from that is that mash temperature does definitely make a difference in the sugar composition of the wort, but it doesn't seem to make much difference in terms of the subjective experience of the final product. Their "low mash temp" beer finished .009 lower in gravity than their "high mash temp" beer, which meant that there was a definite difference between the two, not the least of which a full percentage point in alcohol content. The only problem was that people couldn't tell the two beers apart in triangle tests.

It almost makes me believe that manipulating mash temps might only really be good for changing the alcohol content of a beer without significantly altering it's flavor characteristics.

I recall reading up on that and their results surprise me. I'm not saying it's wrong, but my (subjective) experiences are different. I haven't brewed side by side, but I have brewed the same batch at different mash temperatures. The low mash temp beer came in predictably dry and somewhat thinner than the high mash temp beer. Also high mash temp beers look to have more density in the glass (i.e.: slower moving tiny bubbles rising through the beer, clinging to the glass, and especially when swirling). Head appearance and retention is quite different too. Batch after batch it's the same, and I find mash temp is a reliable predictor of whether a beer turns out dry or dextrinous. I do wonder if process has something to do with it. The methods I've adopted allow for very stable mash temp over a 1 hour period and zero opportunity for heat loss during sparge.

 

[RM-MN]

I recall reading up on that and their results surprise me. I'm not saying it's wrong, but my (subjective) experiences are different. I haven't brewed side by side, but I have brewed the same batch at different mash temperatures. The low mash temp beer came in predictably dry and somewhat thinner than the high mash temp beer. Also high mash temp beers look to have more density in the glass (i.e.: slower moving tiny bubbles rising through the beer, clinging to the glass, and especially when swirling). Head appearance and retention is quite different too. Batch after batch it's the same, and I find mash temp is a reliable predictor of whether a beer turns out dry or dextrinous. I do wonder if process has something to do with it. The methods I've adopted allow for very stable mash temp over a 1 hour period and zero opportunity for heat loss during sparge.

Opinion only!!

I think a lot depends on the milling of the grain as that determines how long it takes from start to finish. If you mill fine (as I do) your grains get wet through quickly and both alpha and beta amylase are active and complete the conversion before the beta amylase has a chance to be denatured. Whether I mash for 20 minutes or 120 minutes makes no difference to the amount of dextrines in my beer.

If the grain is more coarsely milled it takes much more time for the water to reach the center of the particles. While both enzymes are active at the start of the mash, the beta amylase may be denatured before all conversion is done. If then the mash was halted at 20 minutes, much of the starch would remain unconverted and locked up in the grain particles and conversion efficiency would be low. Extending the mash to 60 will increase mash efficiency and give time for the beta amylase to denature so that the wort would have more dextrines. Extending the mash further may or may not result in more efficiency depending on how coarse the milling was and whether the alpha amylase was also denatured. That slower conversion can make the temperature more important in the body of the beer. Would you care to experiment with the differing grain milling and mash times to prove or refute this?

 

[rhys333]

Opinion only!!

I think a lot depends on the milling of the grain as that determines how long it takes from start to finish. If you mill fine (as I do) your grains get wet through quickly and both alpha and beta amylase are active and complete the conversion before the beta amylase has a chance to be denatured. Whether I mash for 20 minutes or 120 minutes makes no difference to the amount of dextrines in my beer.

If the grain is more coarsely milled it takes much more time for the water to reach the center of the particles. While both enzymes are active at the start of the mash, the beta amylase may be denatured before all conversion is done. If then the mash was halted at 20 minutes, much of the starch would remain unconverted and locked up in the grain particles and conversion efficiency would be low. Extending the mash to 60 will increase mash efficiency and give time for the beta amylase to denature so that the wort would have more dextrines. Extending the mash further may or may not result in more efficiency depending on how coarse the milling was and whether the alpha amylase was also denatured. That slower conversion can make the temperature more important in the body of the beer. Would you care to experiment with the differing grain milling and mash times to prove or refute this?

I do experiment with different mash times, usually 1 hour to 90 minutes depending on whether I'm shooting for higher or lower attenuation (with lower and higher mash temp). My grain is milled medium-fine, with smaller but still whole chunks specifically so that conversion doesn't happen too fast. I want to be able to control the amount of dextrins in my beer through temperature and time.

Unfortunately, I can't grind to a superfine setting as my mill tends to jam up. What are the benefits though other than faster conversion time and a little boost in efficiency? Also, if I lose the ability to control the amount of dextrins, attenuation, etc., isn't that a drawback? I'm not debating, just curious how it works for you.

 

[doug293cz]

Opinion only!!

I think a lot depends on the milling of the grain as that determines how long it takes from start to finish. If you mill fine (as I do) your grains get wet through quickly and both alpha and beta amylase are active and complete the conversion before the beta amylase has a chance to be denatured. Whether I mash for 20 minutes or 120 minutes makes no difference to the amount of dextrines in my beer.

If the grain is more coarsely milled it takes much more time for the water to reach the center of the particles. While both enzymes are active at the start of the mash, the beta amylase may be denatured before all conversion is done. If then the mash was halted at 20 minutes, much of the starch would remain unconverted and locked up in the grain particles and conversion efficiency would be low. Extending the mash to 60 will increase mash efficiency and give time for the beta amylase to denature so that the wort would have more dextrines. Extending the mash further may or may not result in more efficiency depending on how coarse the milling was and whether the alpha amylase was also denatured. That slower conversion can make the temperature more important in the body of the beer. Would you care to experiment with the differing grain milling and mash times to prove or refute this?

Let me throw in some more (hopefully educated, ref) opinion. (Warning: it's gonna get deep!)

Neither alpha amylase or beta amylase can break down limit dextrins (branched polysaccharides [primarily amylopectin in the grains we use], which are not fermentable.) Beta amylase creates only maltose (a disaccharide which is fermentable), and is very efficient (read fast) at doing so. Alpha amylase creates random length mono-, di-, tri-, and larger polysaccharides, and is less efficient at creating short chains than longer chains, so it creates fermentable sugar at a slower rate than does beta amylase.

Beta amylase is extremely limited in what it can do by itself. It can only chop maltose units from one end of a polysaccharide chain. It can completely reduce amylose (a non-branched very long polysaccharide [i.e. starch]) to fermentable maltose. However, when working on amylopectin (a branched very large polysaccharide [i.e. starch]), it cannot work past the first branch point it encounters, and thus stops creating maltose from that amylopectin molecule. So, beta amylase, if acting alone, would leave large amounts of amylopectin and large dextrins behind, creating a very low fermentability wort.

Alpha amylase is more flexible in what it can do compared to beta amylase, but it works slower. Alpha amylase can cut amylose at any point along the chain (pretty much randomly.) Given enough time alpha amylase, by itself, can reduce amylose completely to mono- and disaccharides, which are completely fermentable. Alpha amylase can also cut amylopectin at random points along the chains, except at points very close to branch points. This branch approach limit is the reason "limit dextrins" (relatively small, non-fermentable, branched chain polysaccharides) remain in wort, no matter how long you mash. So, also given enough time, alpha amylase can reduce amylopectin to fermentable sugars and limit dextrins.

Alpha amylase also creates a synergistic effect for beta amylase. When it cuts an amylopectin molecule between branch points, it creates a new end on one of the resultant polysaccharide molecules that can be attacked by beta amylase. And since beta works faster to create fermentable disaccharides, this speeds up the overall saccharification process.

Net: beta amylase alone cannot complete the saccharification process, as it will leave behind amylopectin and dextrins much larger than limit dextrins. Alpha amylase alone can complete the saccharification process, but the overall process goes much faster with both beta and alpha working together.

But wait! There is another saccharification enzyme that we tend to ignore. This is "limit dextrinase." Limit dextrinase has the unique capability to cut branched polysaccharides at the branching bond. Every branch that is cut creates more attack points for alpha amylase, and the alpha can create more for beta. This reduces (and theoretically could eliminate, if the limit dextrinase didn't get denatured) the limit dextrins in the final wort, significantly increasing fermentability.

I believe the reason we tend to ignore limit dextrinase, is that it has an optimum working temp range slightly lower than beta amylase, and probably denatures before it can have much effect in a typical mash.

However, as @RM-MN pointed out, gelatinization is the rate limiting step in the saccharification process. None of the enzymes can work on a starch molecule until that molecule has been completely hydrated (gelatinized.) Since gelatinization proceeds from the surface of the grits towards the center, the larger the grits, the longer it takes to fully gelatinize them, and the longer the full saccharification process takes, and the less limit dextrinase can participate.

Since limit dextrinase is only active for a short time at the beginning of the mash. It will have a much bigger effect on a grist with a very fine crush, that gelatinizes quickly, verses a coarsely crushed grist, that gelatinizes slowly. For this reason a fine crush should inherently lead to a higher fermentability wort than a coarse crush, even when the coarse crush is taken to the limits of saccharification, as the coarse crush will be left with more limit dextrins.

Brew on

 

[pricelessbrewing]

Since limit dextrinase is only active for a short time at the beginning of the mash. It will have a much bigger effect on a grist with a very fine crush, that gelatinizes quickly, verses a coarsely crushed grist, that gelatinizes slowly. For this reason a fine crush should inherently lead to a higher fermentability wort than a coarse crush, even when the coarse crush is taken to the limits of saccharification, as the coarse crush will be left with more limit dextrins.

Brew on

First great post as always doug.

Second I believe this is one of the reasons that low temp mash steps (acid/protein etc) were historically beneficial (before awesome malsters made it less than necessary for good conversion), and are still helpful for low diastic power grain bills. One, gelatinization will start occurring before the beta/alpha enzymes start denaturing, so saccharification occurs more quickly once the mash steps are in the right temps. Two, limit dextrinaze has the opportunity to put some work in and help things along.

Moreover I suspect it might be a reason that @Owly605 got higher attenuation than I would expect from his strange slow ramping mash starting at a low temp.

 

[kh54s10]

Didn't read the responses. But temperature and longer time don't necessarily go together for a mash. Most conversion is done relatively quickly so more time may be just that - more time.

Generally I go with: light beers and thinner mouth feel get lower temperatures. Malty, heavy, dark beers that should be a bit sweeter get higher mash temperatures. But there are exceptions to every rule.....

 

[cod3ck]

Didn't read the responses. But temperature and longer time don't necessarily go together for a mash. Most conversion is done relatively quickly so more time may be just that - more time.

Generally I go with: light beers and thinner mouth feel get lower temperatures. Malty, heavy, dark beers that should be a bit sweeter get higher mash temperatures. But there are exceptions to every rule.....

My understanding is time does matter, but only to a point...

Essentially a time set for a specific temp is only to ensure either full conversion, or a conversion of a specific amount of the targeted starch. So this could be relative based on grain crush, mash saturation, fluid flow, and..?

I've read some brewers may have a set recommended time, but once their recipe is figured out, watch the SG of the wort for conversion then move on...

 

[jan_b19]

While prepping for my first BIAB and watched videos to setup my mash profile. I've read pretty exclusively about people mashing for 60min at ~154, but I was surprised to learn about the mash temp and length and how it affects the beers body. Following the guidelines, my first beer should be medium body. Meaning I should be mashing lower temp for longer. Do many people do this?

You have the choice between single infusion mash or step mashing. Since it is your first BIAB I would suggest skipping the step mash because you want to make it as easy as possible the first time. Keeping your mash on one temperature can be hard enough so let's not make it harder.

There are 3 important temperatures for single infusion mashes.

148: light body,
152: medium body
156: full body

So you should mash at 152 for 60 minutes for a medium body. As said above you don't really need a longer mash time except for a certain variety of beers. Mashing lower doesn't mean you convert less sugar. It means that that the sugars you are converting are more fermentable and will add less body (unfermentable sugars) to your beer.

The only time you should mash longer than 60 minutes is:
when you're using a lot of so called low diastatic grains (less than 50°L (Lintner)) Diastatic means grains with a low amount of starch converting enzyme, these are usually really dark grains (roasted malts).
When you are brewing a REALLY dry beer. Because the temperature is so low that you're not converting any unfermentable sugars so it takes a bit longer because the enzyme converting fermentable sugars works a bit slower.

The truth is that 60 minutes is already to long in most cases most mashes are fully converted in less than 30 minutes. So why do people mash 60 minutes? To be sure that every last bit of starch is converted.

The most important thing: Make sure the bottom of your bag is NOT touching the bottom of the kettle when you need to heat your mash (to stay on temperature). The heat will melt and burn the bag and that's obviously not ideal for your beer (happened to me before and couldn't taste any of it in the beer but it's better to avoid).
Also don't forget to mash in (when you add the grain) at a higher temperature 162ish (higher or lower depending on the amount of grain you add) because the water will cool down when you add your grain.