Help with Mash Science

[jceg316]

Hey, I'm currently revamping a lot of my recipes and seeing whether mashing differently will help any if them. From what I understand, mashing at lower temperatures will trigger alpha amylase resulting in more convertible sugars and a higher OG, but "thinner" mouth feel. As these sugars take longer to activate, mashing should take 90 mins. And mashing at higher temperatures will trigger beta amylase resulting in lower gravity but better mouth feel.

So my questions are:

If I mash at about 66c will that trigger them both?
Would mashing for 90 mins instead of 60 at 66c increase efficiency?
Let's say I mash at lower temperatures, can I increase mouth feel by adding a bit more crystal/caramalt?

Thanks.

 

[PHDrunk]

You've got the gist but your amylases are switched. Alpha activates at warmer temps, beta at lower.

Some approximate numbers --- mash between 145-160F. 151F and lower favors beta, 155F and above favors alpha.

Alpha converts faster than beta, but given a good mash pH, a good crush, and decent diastic power, an hour should be sufficient for either.

OG and efficiency should be invariant of the alpha/beta ratio. What changes is fermentability. Favoring beta means starch in the grain is converted to sugars that are more easily digested by the grain, as a result the final gravity is lower than the same beer would be if mashed at a higher temp. FG certainly plays a role in mouthfeel as well as the perception of the beer in general. But as you pointed out, alteration to the grain bill (as well as choice of yeast) can also achieve similar effects.

You'll have to play with both to figure out what you like.


Sent from my iPhone using Home Brew

 

[riderkb]

You can go lower than 66C. I do mine at 60C, then bump up to 70C to ensure full conversion, then bump up to 75C for mash out. I expected to get beer that was too thin and dry, but I like it and have been sticking with it. You can adjust the fermentability by changing the lengths of the 60 and 70C rests. I use 60 min at 60C and 20 min at 70C.

 

[balrog]

Does this help?

 

[jceg316]

Thanks for your replies, yes that graph is very helpful thanks! I can't change the temperature of my mash. My mash tun is a plastic tub w/false bottom and insulation. It can retain heat well, but not increase temp and I don't think putting a gas burner underneath it will do much good.

.
@PHDrunk, thanks for the explanation. If I understand correctly, let's say I do 2 identical brews, the only difference being the temperature, they will have the same OG, but the one mashed lower will have a lower FG?

 

[balrog]

Most things I read about temp change involve water additions, either cold tap or boiling. There are infusion calculators to help determine how much to add of what temp to change the overall mash temp, but there must be headroom left in the tun to allow additions for that to work.
See, for instance http://www.rackers.org/calcs.shtmlor http://www.brewersfriend.com/quick-infusion/

 

[IslandLizard]

Most things I read about temp change involve water additions, either cold tap or boiling. There are infusion calculators to help determine how much to add of what temp to change the overall mash temp, but there must be headroom left in the tun to allow additions for that to work.
See, for instance http://www.rackers.org/calcs.shtmlor http://www.brewersfriend.com/quick-infusion/

Just a note on this:
Those calculators do not count for heat loss due to the mash tun being open and you stirring it for a minute or so. I tend to lose 2 degrees easily just doing that (6 gallon batch). I've been chasing my tail until I started to add those extra lost degrees to the calculators. If you're outside in the cold, combating heat loss can be a real chore.

Instead of adding hot/boiling water, you could scoop out some mash, like 1-2 gallons, and heat it up on the side quickly, while stirring/mixing well, to say 5-10 degrees higher and dump it back in. Repeat if necessary.

You can see why recirculation mashes have an appeal.

 

[mabrungard]

Balrog, nice graph. Did you put it together? I see that it cites several resources.

When I started brewing 15 years ago, I was firmly in the 'mash high' camp. I commonly used 156F to 158F as my target. But over the years, I've found that lower temperature mashing is better for several reasons. The first reason is that I can still produce good body without the potential for worty, dextrinous beer. My years of judging homebrew and tasting commercial beers showed me that the biggest difference between homebrew and good commercial craft beer is that homebrews tended to be underattenuated. Having an adequately dry finish is desirable for almost every style. Homebrewers target body far too much and don't focus on fermentability enough.

One thing that the Pro's have found is that producing well-fermenting wort bumps up the alcohol content slightly and allows them to reduce the bittering level slightly. Both factors are benefits to their bottom line and it improves drinkability. Good drinkability means that their customers are more likely to order another round. Ka-ching!

Another important factor to consider is that dextrins are NOT really that sweet. Loading your beer with dextrins does not make it sweeter. I find that reducing the bittering level and using richer tasting base malts makes beer sweeter. High temp mashes are not ideal for that reason.

I have also heard that dozens of commercial craft brewers tend to focus their mashing schedules in the 146F to 154F range to improve the level of conversion and fermentability. I too have moved my mashing into that range and have found that I still have high body and have lost the worty notes in my beers. I also note that there is some emphasis by the Pro's to avoid excessive crystal malt use. A common guide is to avoid using more than 10% crystal malts in most brewing. I think that is a good idea. I have made beers with up to 20% crystal and they tend to have a distinctive 'crystal' sweetness that can be off-putting. This is just a data point for your consideration.

If body or mouthfeel is lacking in my beers, I use a trick I picked up from Tasty McDole that advocates adding a little bit of flaked wheat to the grist. It definitely builds head and adds body. I find that a percent or two is all it takes and that addition doesn't reduce clarity.

All these factors made sense to me for using lower mashing temps. I see that the range I use, does fall within that Brewer's Window and that makes sense to me.

One thing that the graph cannot factor in, is the effects of time. The longer you mash, the more the starches and sugars will be cleaved into smaller sugars. So, traces for the fermentability and dextrins can be affected by longer mashing time. Just something to consider.

 

[balrog]

I was hoping someone with mash experience would chime in; thanks. I've only ever done small things, and in (one or two) 5G pots I can heat. I always lose more when the "tun" has more head space; I lose many degrees by stirring; I worry about adding too much heat and denaturing the ß enzymes because you cannot go back you can only creep up in temp.

+1 on recirc mash idea.

 

[balrog]

Oh, and mabrungard, I found that "1 hr mash time enzymatic activity" via Google somewhere. I cannot take credit.

It was here: http://missionarybrewer.wordpress.com/2012/02/01/the-brewers-window-what-temperature-should-i-mash-at/

 

[hannibalmdq]

Oh, and mabrungard, I found that "1 hr mash time enzymatic activity" via Google somewhere. I cannot take credit.

It was here: http://missionarybrewer.wordpress.com/2012/02/01/the-brewers-window-what-temperature-should-i-mash-at/

Graphs and variations of it float around alot. It tells you a bunch of stuff about the mash, but it leaves out a lot of variables and how dependant some of them are on each other. Namely that temp and time are not two unique inputs. They are tied to each other quite a bit.

The fact of the matter is there are a lot of things at play regarding enzyme activity and most brewers aren't really in a position to control every aspect of them, so when people start tinkering with temps and times they often don't see huge changes in their attenuation and start to think that some of the effects described are bogus or not applicable on the homebrew scale. It's also very hard to tease out differences in the final product because taste is so very subjective.

While Beta amalyze is active lower in the 140 to 165 range, it starts to denature above 145 and rapidly about 149. It's also the most active at that temp. What this means in practice is you may only get 5 minutes of really intense Beta amylase active with a low 150s mash. After that its all Alpha amylase. Varying your mash temps from 150 to 155 might not really make all that much of a difference in the ferementability of your wort. You might denature the beta amylase a little quicker, but it's also more active before it throws in the towel. So there are competing factors driving the end product to a similar state when mashing in that range.

Also, Alpha amylase doesn't really denature until you get about 170 F. What this means is (assuming you don't do a mash out, which is fairly common) alpha amalyze will continue to be active throughout the mash, probably the sparge, and some of the raise to the boil.

Alpha amylase doesn't just produce dextrins. Dexitrins are a result of the fact that while alpha amylase will hack up starches to little fermentable bits, it can't break the root joints of any amlyopectins so it leaves some dexitrins behind. Alpha amylase will produce fairly fermentable wort given enough time, albeit higher in dexitrin content.

I've seen a lot of instructions that say 60 minute 156 mash, batch sparge, then raise to a boil your 6.5 gallons of wort. The "mash" may only last 60 minutes, but you may well have almost 2 hours of enzymatic activity before the amylase is completely denatured. Given these long activity times, you might not really see a difference in the finished product between a 154 mash and 158. There's just a lot going on.

pH plays a role in enzymatic activity as well, though it's not nearly as pronounced as temperature. Mash thickness is also thought to play a role by offering additional protection for certain enzymes as it varies from thick to thin. I've no opinion on that last one.

What does this mean? I don't know. There are a lot of personal stories regarding mash techniques and what does or doesn't produce differences in the final product. Everyone's system is either a little or a lot bit different, so what some people swear by other calls complete hokem.

The good news is that it's really not that difficult to produce a decent wort. The low 150s mash is widely accepted as a good mash range because there are so many factors driving the enzymes to decent conversion and decent ferementability at those temperatures, regardless of the other inputs to wort composition. I encourage you to tinker with it, but please set your expectations accordingly.

The science behind this stuff is pretty well understood. It's practical application for your equipment and process is highly variable. None of that precludes any of us from making great beer in a variety of ways.

 

[jceg316]

Thanks, there's plenty to think about. I'm tempted to see what my IPAs and lagers taste like when I mash lower, but any Belgian style I might keep quite high. Those beers have very thick mouthfeel so would benefit from higher mash temps.

 

[mabrungard]

but any Belgian style I might keep quite high. Those beers have very thick mouthfeel so would benefit from higher mash temps.

Hmm? That is not what I find in most Belgian styles. They go out of their way to make sure that their beers are well-attenuated and often include simple sugars in the formulation to enhance fermentability. Its not until you get into the golden and dark strong ales that I find Belgian beers to have thicker mouthfeel.

 

[jceg316]

Hmm? That is not what I find in most Belgian styles. They go out of their way to make sure that their beers are well-attenuated and often include simple sugars in the formulation to enhance fermentability. Its not until you get into the golden and dark strong ales that I find Belgian beers to have thicker mouthfeel.

Interesting you say that because I'm trying to make a golden ale ;-). I also want to make a tasty brown ale Belgium style.

Whilst a little off topic, I've been reading Brew Like a Monk by Tim Web and Stan Hieronymous (sp?) A must read for any home brewer wanting to make some Belgian style beers.

 

[StMarcos]

hannibal says it well. You need to consider that the various enzymes can denature rapidly above certain temps. It can be the case that the kill rate is more important than the Temperature/pH activity optima....

 

[PHDrunk]

@ jceg316 --- yup, same wort with different mashing temps should only effect FG, not OG. For Belgians, generally people mash pretty low as I understand it. For Saisons, you want really high attenuation for an easy drinking, delicate beer. With darker Belgians, from what I've read people still mash fairly low and get the mouthfeel from addition of caramel malts (special B, caramunich, etc.) and candi sugar in the recipe. Furthermore, Belgian yeasts are said to lend a lot to the mouthfeel and "thickness" of the beer themselves. Tried to find a link for this but I don't have the time to search right now, if I find it I'll post it.

That being said, there really are no hard and fast rules, do what you like. For example, Lagunitas reportedly mashes at 160F for their IPA: https://www.homebrewtalk.com/f36/mash-too-high-lagunitas-ipa-clone-128971/. Most important thing is too brew a lot and use the product as feedback.