Couple of fine tuning partial mash questions

I am getting back in the brewing groove and making a slight move from steeping specialty grains to stovetop partial mashes. I am happy with the results so far so I am not looking to make any big changes I just want a better understanding of some of the "whys" and the difference they make in the brews.

I think I have a pretty good feel for the part mash temperature plays.

What about water volume? The recipes I have used so far call for a 2 gallon mash. The boil pot I use just sets up better with 3 gallons because I can keep my grain bag off of the sides and the bottom easier. My pot holds the temp pretty well, but if I need a touch of heat towards the end of the mash I just feel more comfortable knowing the grains are suspended and not touching the pot. Does this matter that much since it is going to end up at 5 gallons anyway and I am not taking any gravity readings until all of the extract and water etc is in the mix? So there is never a real efficiency check.

Same goes for the sparge/rinse. I am just not grasping the reason for 1 quart per 2lbs of grain. My understanding is that the idea is to get as much of the good stuff out of the grains as you can. Is there a reason to limit it to an arbitrary amount as long as the temp is right?

I know I have some more questions but drinking beer is starting to win the fight against talking beer so feel free to throw in bits of knowledge.

I will explain it in full grain terms. The grain to water ratio is needed to ensure the enzymes have the conditions to convert the starches into sugar. Too thick (not enough water), or too thin (too much water) of a mash does not create an environment that the enzymes prefer to do their job. (It gets really complex, thicker mashes are better for some enzymes, while thinner are better for others). Ratios and water amounts are given in recipes so you know how much water is needed for you to brew. Sounds obvious, but you dont want to waste time and energy heating more water than you need, or worse.... not heat enough. If you follow the recommended ratio of water to grain for the mash, and sparge it with the recommended amount of sparge water, you "should" end up with the recommended preboil volume. All this depends on your equipment (efficiencies, losses, preferences etc.) Partial mashes are more about getting the flavor from the grains than actual sugars from starch conversion (although that is a purpose as well).

Nanobru said:

I will explain it in full grain terms. The grain to water ratio is needed to ensure the enzymes have the conditions to convert the starches into sugar. Too thick (not enough water), or too thin (too much water) of a mash does not create an environment that the enzymes prefer to do their job. (It gets really complex, thicker mashes are better for some enzymes, while thinner are better for others). Ratios and water amounts are given in recipes so you know how much water is needed for you to brew. Sounds obvious, but you dont want to waste time and energy heating more water than you need, or worse.... not heat enough. If you follow the recommended ratio of water to grain for the mash, and sparge it with the recommended amount of sparge water, you "should" end up with the recommended preboil volume. All this depends on your equipment (efficiencies, losses, preferences etc.) Partial mashes are more about getting the flavor from the grains than actual sugars from starch conversion (although that is a purpose as well).

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That makes sense. I wonder how much thought AHBS puts into the instructions they send with their partial mash kits. So far everything has been 2 gallons and 1 quart per 2 lbs.

Working well so far so I think both "if it ain't broke" and "try it both ways to see how/if it changes" apply.

I definitely agree. How would you know if it is just hoppy enough, if you have never made it too hoppy? By the way, with all grain brewing, ratios are usually 1.1 to 1.3 quarts of water to 1 pound of grain