Enzymes, Denaturing, and Mashout

[MrBJones]

An interesting and potentially useful article in BYO can be found HERE. It's really geared toward step mashing but there's also information applicable to mash outs. We're often told that conversion entirely stops at around 170º . It turns out, though, that different enzymes denature at different temperatures.

For me, the greatest concern for a prolonged mash or sparge is that the temp might drop enough to result in too much Beta-amylase conversion, which in turn can make for a thin bodied finished beer. But it seems that if you can get the temperature above 160º - which isn't difficult - the beta will denature, solving that problem. So, though 160º isn't a true mash out, it might do what you want.

Table from the article

 

[dmtaylor]

Another interesting thing is that each enzyme doesn't all just magically denature at a given temperature. Some will, some won't. It takes time for the enzyme to completely denature. So, for example, if you accidentally mashed in at 170 F but immediately recognize this as a problem and add cool water within say 5-10 minutes, your batch will likely still turn out just fine. Might want to do a longer mash then just to be on the safe side, but don't be super surprised if you still get good conversion and attenuation. Although if much longer than that 5-10 minutes... well, good luck.