Single infusion temp change

[gwashingk]

So if I want a beer with body on the lighter side, is there really any harm in starting my mash at 155 F and letting it drop down to 145 F? From what I understand the higher mash temps (154 to 167 F) produce larger sugars, and lower temps (130 to 150 F) break them down to small sugars. So if I start high and make more large sugars, when the temp drops the mash will just be breaking those down to small sugars. I imagine the result would be a mostly light body beer, but is there really any reason to keep the mash temp so consistent if I am aiming for a lighter body anyway?

 

[IvanBrew]

The potential problem with going this route is that beta amylase begins to denature around 149. If you start high and fall back, you may not have enough beta amylase left to get your balance where you'd like it.

Denaturing is dependent on time, temperature, and pH (among other things), so it may or may not actually be a problem for your mash.

 

[DSully]

The higher mash temperature will eliminate the enzymes that do the work at the lower temps, and letting the temp drop will slow down the enzymes that do their work at higher temps. If you can get The Brewers Companion or Homebrewing for Dummies you should read them. Those explain real well

 

[dobe12]

I agree with the above. It doesn't really work the way you think. Once you get your temps up past a certain point, you won't have the right enzymes to convert the starches to smaller, highly fermentable sugars.

I think what you want to do is mash lower (148'ish) for 20-30min, then bump up your temps to 155-158 range and hold for a bit longer. I'm not certain on times, but this should help you get a mix of highly and less fermentable sugars.

 

[duboman]

IMO to achieve what you want in the finished product simply do a single infusion mash at 148-150 and you'll have a light to medium body drier finishing beer.

If you're really set on doing a rest then 20 minutes at 135 and then raise to 150 but with today's highly modified malts the single infusion at the right temp is fine

 

[gwashingk]

Ahh, thanks, seems obvious now. If the temperature is too high it will denature the beta amylase enzymes and there won't be enough of them left for further conversion by the time it drops down to their comfort level. I knew there had to be something that was escaping me.

 

[narl79]

Palmers book describes this process pretty well. I had to read it a few times but it made a world of difference.

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