Originally Posted by iverasp
Would it be possible to reduce the amount of mash water and rather use more sparge water in several additions in order to accommodate for a smaller-than-practical mash tun? In my first brew I used 6kg of malt and 16L of mash water and my mash tun was filled to the brim (~28L tun). For my next brew I would like to do an IPA but the increased grain bill (~9kg) would suggest I have to make a smaller batch than the recipe suggests (5 gallon) or do other adjustments.
Anything is possible; some things aren't recommended. I'm not good with liters, but I'll give it a shot.
I typically do ~0.95l (1.25qts) per 0.45kg (1lb) or grain. With your mash tun size that would obviously overdo it for the 9kg grain bill. Many people recommend a 1:1 ratio which would basically be 1l to every 0.5kg. At this rate you would need 18l of strike water. You could go with less, but I think efficiency would suffer. I would either brew a smaller batch (like you said) or buy new equipment.
"The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature."