avshook

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I do a single step infusion mash and I usually hit a temperature of 152-156 and my beers end up a little sweet for my taste. So, I'm trying a mash at 148 today. How low can I go and still get full starch conversion? I know I have to mash longer at lower temperatures, but how low is too low for a single step infusion mash?
I'm doing a 10 lb batch, 9 lbs of 2 row, 1 lb of crystal.

babalu87

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You can get conversion at 143 so RDWHAHB

148 will make a nice dry beer

TexLaw

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148 is fine, but I wouldn't go any lower than that. I cannot be precise, off-hand, but getting much lower will markedly decrease alpha-amylase activity. That alpha-amylase is important, as it exposes more non-reducing ends for the beta-amylase to chew up into maltose. At the very least, you will slow your conversion down for no good reason.

If your beers are too sweet for you, you probably ought to look into changing your hop regimen more than your mash.


TL

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XXguy

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Why not just cut back on the Crystal? Crystal adds sweetness, and a pound seems like quite a bit to me.

I'd rather mash at 152 with less crystal.

z987k

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Remember that unconverted starches are not sweet. They in fact have very little "taste". I can make a highly dextrinous wort that has no sweetness at all.
If you think you are not getting full conversion you need to take other steps.

I would do an iodine test to check for conversion if you are really worried about it.

However to you're question, how low can you go, you should be able to go as low as even 130, and if held long enough will convert, however this is highly inadvisable. Maximum fermentability is usually going to be in the 145 range where alpha, beta and limit dextrinase are all able to work (alpha being rather slow at this temperature).
Highest fermentable yield is usually in the 148-150 range.
You can also get "full" conversion at much higher temperatures. 158 will give you a fully converted wort(fast to), with low fermantability, so lowering the temperature does not increase conversion as long as you are within the accepted range for the amylase.
Obviously these should not be the only deciding factors when choosing a mash temperature.

Basically what I'm getting at, is your mash temperature has little to do with the sweetness of your beer.

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david_42

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It isn't just a matter of conversion. The starches in barley don't gelatinize well below 148F. You can make up for that by longer mash times and some extra stirring.

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kanzimonson

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+1 to what z987k says. If you mash at higher temperatures, you produce unfermentable sugars. But even though we call these "sugars," most are not perceptible as sweet to the human tongue. If you mash at lower temperatures, it's true you'll produce simpler sugars, which are more easily consumed by yeast. BUT, yeast still have a fairly consistent range of attenuation levels. Once they reach these upper levels, their energy stores run low, and then they kick out. Consequently, you'll be left over with some of these simpler sugars you created during mashing, and your beer will be perceived as sweeter.

So I think that mashing at lower temps will give you the exact opposite effect you're looking for. Use less specialty grains in your beers and up the hop bitterness instead.

Chu

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So, I am trying to learn all-grain and following recipes, but my beers are coming out 'thin' without much body at all. I am concerned that I may not be maintaining a high enough mash temp. Is this likely a result of too cool a mash? Would mashing for longer times help if my mash temp was too low?

Calichusetts

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Or you could just add honey to dry it out and increase the ABV...don't know if you like your beers light or heavy

Junkster

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The OP doesn't mention terminal gravities or yeasts used - another variables to consider?