I’m curious about changing temperatures during the mash. If I start at 150, and 90 minutes later I’m at 146 or 147, how will the result differ than if I had kept it at a steady 150? As long as I’m in the beta range, beta conversion will go on, right?
For the most part, yes. Reaction rates are temperature dependant, so you may get full conversion a bit faster if you could hold it at 150 the whole time. But a 3-4 degree loss over 90 minutes isn’t that big a deal.
Cool. But if I get up into the range of 156, that destroys the beta amylase, so that even if I drop the temp to 150, there will be no beta conversion, only alpha conversion, is that right?
Sort of. The enzymes don’t denature all at once, but it is pretty much permanent for the ones that do. So you will probably see a decrease in beta amylase activity. It will depend on what temperature you hit, how long it was at that temp, and the initial enzyme content of the malt, to determine how much enzyme activity will remain as the temps fall.
At the temps you’re talking about- you’re going to get a thin bodied beer like a Pilsner or pale ale.
There is a huge difference between 150, 152, 154, 156, and 158 mash temps. The most noticeable will be the body of the beer. The second will be efficiency. I’ve been to way too many breweries where their stouts have the same body as their pale ales. The reason is they “set it and forget it” and the mash temp drops over the course of the mash.
You’ll never really get a great porter or stout unless you can hold the mash temp +- 1 degree.
If this is a problem- you’re better off starting on the high side and dropping into your target temp than you are trying to raise the temp to target.
Higher temps conversion rates are quicker but less efficient. If you’re temps drops below the body style you’re shooting for you’ll also get higher alcohol but a drier beer.
For medium bodied or rich bodied beers raising the temp to mash out is critical to “lock in” the conversion versus continuing conversion during mash out as the temp drops- reducing body, increasing ABV, reducing residual sweetness.
This doesn’t match my experience very well at all. There is a huge difference between 147F and 162F mash temps, but I haven’t seen a significant difference in my end results with mash temps ranging between 150F and 155F or so. Lagunitas mashes their IPA at 160F, but it doesn’t have a body like a stout. Malt today is so hot with enzymatic content that mash temperature just doesn’t have a huge effect unless you’re at relative extremes in the range.
I completely disagree that you need to be able to hold your mash temp to within a degree to produce a good porter or stout. Most homebrewers don’t have that capability, but still produce excellent full-bodied beers. Like any beer, you may have to adapt a recipe to fit your system in order to really dial it in. But the ability to do so is well within the reach of a knowledgeable homebrewer.
Your mileage may vary- you can do anything you want. Mash temp won’t make or break your beer. It’s still beer. But…
A lot is technique and equipment. I understand if home brewers can’t keep their mash temps within 2 degrees variant- but it doesn’t mean you don’t try and you’d better understand what it’s going to do to your beers.
At our brewery we see a distinct difference in the body and texture of the beers most notably 150 and under, 152-154, and 156 and up.
I know a lot of home brewers who mash at 152 exclusively. Fine. It’s still beer in the end. But as a craft if you want to brew the best beers you can to style- mash temp is important.
As mentioned, I’ve been to a lot of breweries where ALL their beers have the same body feel ranging from pale ale to stout. Stable mash temp is the number one reason.
Adjuncts and body filler grains help with the body and mouthfeel but the science in the end dictates. Starch conversion at alpha or beta temps produce different results.
Lower mash temps- increased conversion, less residual sweetness, a drier mouthfeel, higher ABV, thinner body.
Higher mash temps- lower conversion, more residual sugars, lower ABV.
You would never suggest brewing every beer to one mash temp for a reason.
People don’t brew pilsners at 158 and people don’t brew stouts at 149. You can if you want, it’s all about the pallet.
Lagunitas has a distinctly richer mouthfeel and residual sweetness than compared to a Pilsner. If they brewed it at 149 it wouldn’t be the same beer.
We’ve brewed over 70 different beers this year alone and I would never consider brewing them all at the same mash temp. I can measure the result of the temp dropping even 2 degrees for a prolonged period when we see an increase in efficiency- I know we won’t get the same mouthfeel or residual sweetness in the final product.
You can see for yourself if you use Beersmith by changing the mash profile- check out the ABV with each temp profile- it’s different. So will the ensuing mouthfeel (unconverted starches) and residual sweetness (long chain un fermented sugars).
There’s a lot of moving parts into making good beer at any scale- mash temp is another important tool in the toolbox.
I agree the differences may be minute- but there are differences in mash temp.
From a brew house stand point, there is a difference.
We can see a difference in brewing efficiency, attenuation and mouthfeel at 3bbl batch sizes. I can measure the difference. It may be just a few points but mash temp does have an effect.
If we brew the same beer, same grain bill, same yeast, but the temp is slightly lower- there is a difference.
As a home brewer, it may not matter. As the brewer for our tasting room- you do your best to brew a consistent product and mash temp is just one of the many control points in the process.
If you can control your mash temp- great; if you can’t it doesn’t mean you’ll make bad beer- it just may not be ‘exactly’ the beer you designed and you may not ‘exactly’ be able to brew it again. Not the end of the world. It’s still beer.
If I was brewing 3 bbl at a time, that might be relevant. But I’m not. FWIW, I use a Zymatic which controls temps at least as precisely as your system. I still can’t tell a difference between 152 1nd 154. And I’m a reasonably good taster.
While I can measure it and I know what it means to the final brew, I admit it is easier to detect the differences by taste from 152 to 156. Same down from 154 to 150 (again plus or minus a degree of error).
But regardless, drifting 4 (or more) degrees during 60-90 minutes of the mash does make a difference in your beer in multiple ways.
I think temperature makes a bigger difference at the ends of the spectrum, less so at the middle. I like a Mild at 158F or a bit higher. Pilsners are better near 150F or just under. If I miss by a degree or two on the low end, I don’t sweat it much and add heat only if loses more than another degree or two (direct fire capable). If I start a bit high, I will simply stir it down to the right temperature. Strike water is a different thing. I try to get it very precisely at the right temp (so I don’t miss the mash temp by much). I will overheat strike water and then cool it with frozen water bottles to get it dialed in as a starting point. But for most ales in the middle, I see little difference between 152F to 156F and don’t sweat any drift from that point (but I try to prevent large drift, of course).
For us homebrewers without mash temperature control, I think this is as good as we can get. I mash in a Denny-cooler, and, for a 60 minute mash I may lose about 2 degrees or so. But I ALWAYS lose about 2 degrees. My 152 degree mash is really a 152 sliding down to 150 mash. Every time. Also, I probably don’t have close to the precision that most commercial brewers do regarding all sorts of weights and measures (and don’t even get me started about how many yeast cells I pitch), so I do expect tiny variations batch to batch. But if I could keep my mash temp at precisely 152 for the entire 60 minutes, I don’t know that my palate is sensitive enough to detect any difference at all over my current process.
I don’t think anyone would advocate that you just pour some hot water in your mash tun, stir in your grain, then call it a day without ever measuring a temperature. You need to know and control your strike temps, but everything else you can dial in based on your own system. Mash temp is important, but there are many other factors that also decide body and attenuation in a finished beer.
And frankly, if you can’t taste the difference between 2 beers, then there’s no difference as far as I’m concerned, regardless of what the numbers say.
In the end, each brewer needs to understand his or her own system. If you want more body, then boost your mash temps by a few degrees, hold it for a shorter time, use a less attenuative yeast, etc. If your mash temp drops a few degrees during the mash, then maybe you need to mash your stout a few degrees higher, or bump up the flaked barley, or whatever. Easy enough.
FWIW, I mash barleywines at 147 for 2 hours, but they still end up with a body like a sumo wrestler.