23 replies to this topic

[stangbat]

I specifically bought a scale for our 2007 Christmas party hoping the Blktre would get it. He didn't. I tried.

[NWPines]

If I understand correctly, you are brewing a greater volume of beer, using the same mash tun. This implies to me that your grain bill is larger, proportionate to the increase in batch size. Thus, you would have a greater grain bed depth to sparge through. What I'm wondering is if the increased grain bed depth has allowed for a more uniform flow through the bed when you are sparging, and an increase in efficiency. Palmer talks about grain bed depth and it's effect on efficiency in "How to brew", discussing it in terms of fluid mechanics. What he says is, "...increasing the grain bed depth chages the proportion of the grain bed that is outside the convergence zone, which increases the proportion of uniform flow, which increases the extraction efficiency as a whole."

This sounds like a reasonable explanation to me. I'm also wondering if you are sparging with a larger volume of water per unit of grain? If so, that should also increase your efficiency.