Originally Posted by avshook
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.
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.