I do 1.25 quarts per pound of grain. However, if the mash is too cool, I'll add more. Does it really matter? Why can't I just put in enough so my first runoff is 1/2 my final desired (preboil) volume? Thanks.
Mash thickness matters because a mash is an enzymatic reaction and the concentration of reactants, enzymes, and reaction products will effect the outcome of the reaction. That said, there is a lot of room for error and you shouldn't run into problems with mash thicknesses of anywhere from about 1 qt/lb to 2 qt/lb. So to answer your question yes, you could mash thinner (significantly so) than 1.25 qts/lb if you wanted to.
Good. 'Cuz I really effed up and way undershot my target temp and had to add a bunch more water... Probably ending up around 2 qts (maybe a little more) per pound. In retrospect, could I have runoff the water, reheated it, and poured it back in? This would have kept me in ratio without going over.
Here's a good article on the subject. http://byo.com/mashing/item/1110-managing-mash-thickness I tend to go thicker for stouts/porters/barleywines, thinner for sours/pale ales/ipas.
German brewers use thinner mashes, 2.5 qt/lb is common. BIAB brewers go even thinner, according to a guy in the club that mashes in a bag.
In retrospect, you could pull a decoction to heat the mash water. This is done by pulling the GRAINS to heat. NOT the WORT. I'm assuming this is because the enzymes reside more in the strike water than the grainbed after infused.
Hmmm, how do you do that? Have the grains in a big bag and heat them in a pot? I'd think they'd burn very easily...
Decoctions are pulled from the mash. Typically with some sort of sieve or strainer. You throw the grains in a pot and work it on the stove. You have to stir like hell when you're getting up to a boil. After you get it good and hot everything loosens up a little and you don't need to stir constantly. It's the bain of brewing. A huge PITA! This does a pretty good job of explaining it:
I agree. I think the next time I do a decoction it will have to be a double batch though. I'll make it worth an 8 hour brew day.
The big deal around mash thickness is about the performance of the mash, what kind of sugars you get out of the mashing process, how log it's take to convert the sugars. If you got your mash at the right range, you will be fine. You can read more about it here starting at the 3td paragraph.
