Is 140 too low to mash?

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dsuarez

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I mashed my grains for a belgian blonde and the temp settled at 149...pretty much what I was shooting for. Nice and dry. I Checked it 15-20 minutes later and it was at 146. 45 Minutes later it was down to 140.

Was this too low for enzymatic activity? I raised it a bit to 142 with boiling water, and let it sit for a little over 2 hours just to give it some time. I have never had this problem before though! What is a mash at 140 like? Anybodyever mash this low?
 
Did you do an iodine test? The temperature often varies through the mash, did you stir each time you measured the temperature? Too late to change now, the beer will tend to be very dry with not much mouth feel. I mash in the 68-69 deg c range (154 - 156 deg f)
 
I didn't have any iodine. But my gravity was exactly where I was shooting for (actually a little higher). Is it safe to assume that this density comes from sugars? in other words, would my OG be lower than expected if full conversion did not occur?
 
No way of testing because I don't have any iodine around. But I left the mash for 2.25 hours before sparging just to be safe.
 
140F as the only rest might be a bit low for mashing as the majority of the starch doesn’t gelatinize until the mid 140s. Gelatinization of the starch is theoretically not necessary for conversion (just look at a germinating seed, it uses the starch w/o gelatinizing it first) but w/o it the conversion process takes much longer. As a result there will always be additional rests if you would dough in that low.

BUT, you didn’t start there ;). You started at 149F which gelatinized most of the starches. And when the temperature now drops the starch remained gelatinized and the enzymes can work on it. Albeit a little slower at the lower temp. But the lower temp helps the beta-amylase to survive longer. The result is more maltose and better attenuation. Just what you needed. Since your gravity was as expected I assume that your conversion efficiency (amount of starch converted) was also as usual.

The interesting thing about the iodine test is that it not only detects native starch, but also long dextines. The latter are much more predominant towards the end of the mash anyway. These long dextrines give a reddish color w/o iodine and can also form a haze in the beer as the presence of alcohol reduces their solubility. It is a good practice to always mash until there is no color reaction w/ iodine. But I have also lautered mashed there weren’t quite at this point (especially when using malts with lower DP) and the beers turned out fine. But my goal is always to completely remove the reaction with iodine.

Kai
 

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