Originally Posted by carrotmalt
Here's a malt chart
that you might take a look at to get an idea of the potential for popular grains. I wouldn't think steeping would give you very high efficiency, but:
If you add say a pound of crystal 20 (1.035) at say 60% efficiency, that would give you
35 * .6 = 21
add that to 5 gal batch and get
21/5 = 4.2
So maybe you'd be adding around 1.0042 to your OG. That may be a bogus method if the steeping grains can't convert by themselves.
It's probably a minimal increase, but you could also check your gravity after steeping and calculate how much less extract you need accordingly. I probably wouldn't bother and would just take note of the difference after doing a batch.
You are absolutely correct in your calculations. I use 50%, but it's a crap shoot as to what you really get from steeping.
Steeping grains do not need to be converted; it's already sugar. You just have to 'rinse' the sugars out.
Steeping grains have more unfermentable sugars than ordinary grain. Not sure what the content is, but would guess the sugars are about 50% unfermentable.
Result: The use of 1 lb of steeping grain in 5 gallons (Crystal, Black, Chocolate, etc) will add about 0.25% to the final alcohol level. You will get more from the sugar you use to prime with.