Fermentability Myth Bustin: Crystal Malts

[biertourist]

A fantastic experiment over on the HomeBrewTalk forums; a member fermented out mashes with a large percentage of crystal malt and found that the old statement that crystal malts are primarily unfermentable sugars from carmelization in the grain is pretty much untrue.

http://www.homebrewtalk.com/f128/testing-fermentability-crystal-malt-208361/index11.html

He also proved that you get 20% more extract out of crystal malts when mashing them vs. when just steeping them. (There's plenty of starch still left in the grain.)

The sugars, even in the darker crystal malts are still VERY fermentable; a mash made from 100% steeped crystal 10 malt was still 50% fermentable; when the crystal malts were mashed they proved to be almost as fermentable as the basemalts...

In typical mash percentages you're likely to see less than a 1 point increase in finishing gravity.

To reduce fermentability control mash temp, times, and mash diastatic power.


Wow, wow, wow.

Adam

[biertourist]

If you want some residual sugars, adding the crystal malt for only the last 15 minutes of the mash might be a way to go; the darker crystal malts provide less starch and more simple sugars.  I'd recommend grinding them finer than usual, too.


Adam