What is cold steeping specialty grains all about? How do I do it? What does 'cold' really mean? How long does it take? Advantages and disadvantages?
Cold steeping is supposed to give you a smoother taste from dark and specialty grains that can impart ashy, acrid flavors when steeped in hot water.
Cold steeping means actually steeping your grain at room temperature (not in ice water), and steeping it for 6-12 hours. The process is very similar to cold steeping coffee (and it's also done for similar reasons).
Also remember that hot water is more soluble than cool water, so you might need to use more water to dissolve as much sugar out as possible. This article recommends 5X the weight of your grain in water.
So I would summarize:
Here is info on cold steeping from the legendary Dr. George Fix...
"Question to Dr. Fix:
The talk was in the NCHF at Napa in October. Those folks on the left coast really know how to do a beer festival! The cold steeping procedure was designed to maximize the extraction of desirable melanoidins, and at the same time minimize the extraction of undesirable ones. The former are simple compounds which yield a fine malt taste. The undesirable ones come from more complicated structures. Polymers with sulfur compounds tend to have malt/vegetable tones. Others yield cloying tones, which to my palate have an under fermented character. The highest level melanoidins can even have burnt characteristics. The cold steeping procedure was developed by Mary Ann Gruber of Briess. My version goes as follows.
Mary Ann has had good results by adding the steeped grains directly to the fermenter without boiling, however I have not tried that variation of the procedure.
The upside of cold steeping is that it works. The downside is that it is very inefficient both with respect to extract and color. In my setup I am using 2-3 times the malt that would normally be used. As a consequence I have been using it for "adjunct malts" such as black and crystal. I also am very happy with the use of Munich malts with this process when they are used as secondary malts. "