Originally Posted by Frodo
I wasn't talking about mashing. I was talking about rinsing the sugars from the grain a.k.a. sparging. If you dunk a bag of grain that's been partially mashed or steeped, that's a rinsing (sparging) process. I was assuming that the proper method would be used for whatever particular specialty grain used; i.e. if it's a malt that needs to be mashed that it would be included in a partial mash process with some base malt, and if it doesn't need to mashed to convert starch (eg. crystal malts) then steeping would be sufficient.
I understood that. And I certainly understand that dunking a grain bag in water is a rinsing process (give me a little credit here, ya?
) The point of yours that I was objecting to, specifically, was the claim that you can expect the same extract efficiency (70% is the number that you used) from steeped specialty grains as from mashed specialty grains. While the rinsing process might be the same for mashing and for steeping, a steeped grain doesn't have as many simple sugars to rinse off in the first place. Even with the same grain, mashing converts starches that steeping doesn't.
This idea that crystals, etc. are "pre-mashed" gives too strong of an impression. While the malting process of some types of specialty malts converts _some_ of the starches into things extractable by steeping (and thus useful to extract brewers) not all of the starches are actually converted when they leave the maltster. These unconverted starches represent a hard upper limit to your potential extraction without enzymatic mashing. While what you are describing is mechanically the same as a batch sparge, there just aren't as many sugars to rinse off.
The extent to which this happens certainly varies from malt to malt; a crystal-120 likely needs less help than a crystal-20. A honey malt, a special B, or a Munich needs a lot of help. The 30% that gets tossed around is a loose and fast average, but in my experience it's generally going to be a lot closer to the right answer than 70%.
There's an essay I read a while ago by Charlie Bamforth that explains this better than I can, but I can't for the life of me find the reference right now. Here's
another article that says something similar.