All this talk of mashing thin got me curious to try it for myself. Today I mashed two small 5lb batches of a Vienna lager grist, 2lb pils, 2lb Vienna, 1lb light Munich. On the first I used a 3qt/lb mash ratio and got 75% efficiency preboil. On the second I used 3.2qt/lb and also got 75%. I mashed at around 150F for two hours in each case, then just drained and boiled.
I did two batches because I inadvertantly added double the hops to the first batch, so my solution was to make another with no hops to get the intended IBUs. Poor reason, but replicating an experiment is sound science.
Is this right? 3qt/lb for the first, 3.2 for the second? I would think that 0.2 qt/lb wouldn't really be the difference between thick or thin.