Efficiency, wort left behind, sparging (BIAB)

[z-bob]

That extra .67 pounds of sugar is the best case. It assumes the sugar concentration in the water retained in the grain is the same as in the sparge water. That's a good assumption if you give it enough time to equalize...

I did a no-sparge brew once before and my efficiency was terrible. But it was a small batch of high-gravity beer, and my efficiencies were not all that good anyway. I should have known better

 

[doug293cz]

That extra .67 pounds of sugar is the best case. It assumes the sugar concentration in the water retained in the grain is the same as in the sparge water. That's a good assumption if you give it enough time to equalize...

I did a no-sparge brew once before and my efficiency was terrible. But it was a small batch of high-gravity beer, and my efficiencies were not all that good anyway. I should have known better

Yes, that is one of the fundamental assumptions of the model. Stirring after adding sparge water will speed up the process of concentration equilibration by orders of magnitude.

High gravity beers are on the right side of the chart. More grain means a larger fraction of the total wort, and thus a larger fraction of the total sugar, is retained in the grain. This is the cause of lower lauter efficiency for big beers. You could also have been affected by lower conversion efficiency. Thicker mashes convert more slowly (ref), and so may suffer from lower conversion efficiency if mash times are too short.

Brew on