I know that this has been discussed in many posts, but I could not find one that fit my case specifically. After many extract brews, I decided to try all grain. I bought the all grain kit Surly Bender, which was supposed to have an OG of 1.060. Things I think I did right…I used brewgr website to calculate water volumes. My buddy and I were shocked when we ended up with the correct water volume measures at every turn (6.5 gallons from mash tun, 5 gallons into fermenter). At this point, we thought this was going to be easy. I took a hydrometer reading after boil and cooling (as it was going into fermenter). I used brewgr website to adjust reading for temperature of wort and came out with 1.049, well below the 1.060 that the recipe claimed. With water volumes dead on, does the problem have to be with our mash and sparge technique? We did a batch sparge and except for a small time where our temp dipped to 150 degrees, we were at our goal temp of 153 degrees for most of the 60 minutes.

Here is where I am thinking the problem lies: After the first running (about 2 gallons of wort to kettle), we added the remaining sparge water (volume calculated on brewgr) to the mash tun. The temp in the tun was about 155 degrees. After a good mixing, we started to drain right away. Should we have let the grains soak longer?

Soak time doesn’t matter at all. Batch sparging will get the same sugar out if you mix then drain immediately or if you let it sit for some time.
The fact that your first runnings were somewhere around half the volume of you second runnings will hit your efficiency some (you get best efficiency with equal running, meaning the same volume recovered from each running, not the same volume of water added), but the biggest factor for this is almost always related to how fine the crush is.
If you bought pre-crushed grain, take your results into account so you can adjust to account for this next time. If you crushed the grain yourself, consider tightening the gap on your mill for the next brew.

[quote=“rebuiltcellars”]Soak time doesn’t matter at all. Batch sparging will get the same sugar out if you mix then drain immediately or if you let it sit for some time.
The fact that your first runnings were somewhere around half the volume of you second runnings will hit your efficiency some (you get best efficiency with equal running, meaning the same volume recovered from each running, not the same volume of water added), but the biggest factor for this is almost always related to how fine the crush is.
If you bought pre-crushed grain, take your results into account so you can adjust to account for this next time. If you crushed the grain yourself, consider tightening the gap on your mill for the next brew.[/quote]

ALL OF THIS^^^^! Keep in mind that you have to find your own efficiency and adjust the recipe accordingly. And as was said, crush is the #1 variable in efficiency. Northern Brewer is a great company, but there are consistent reports of low efficiency due to their crush. Also, there’s a MUCH easier way to determine water amounts…mash with whatever ratio you like (I go around 1.75 qt./lb.). After your mash runoff, measure how much you have in your kettle. Subtract that from the amount you want to boil. The answer you get is how much sparge water to use, since there will be no further grain absorption. Take a look at www.dennybrew.com for details and ideas. FWIW, I’ve brewed 485 batches using these principles and equipment.

Ok…so I inputted all of the grains in recipe to Brewhouse Efficiency calculator and it says that I had 73% efficiency. The recipe said OG should be 1.06. That seems like a high efficiency to be that far off stated OG? BTW…the grains were milled by Northern Brewer. And the water calculation that you stated, Denny, does seem a tad easier. But nonetheless, I was impressed by how spot on the water volumes were with brewgr. Might have just been a fluke?

Just to further make RBC’s and Denny’s point, I usually have NB double crush my grains for BIAB, but this last time if forgot to specify with the order. First up was a hefeweizen, hit all the numbers except preboil SG–was about 8 points low–had to add dme. Next two were a pale ale and a kolsch. I very carefully ran all of these grains through my vita mixer to get a better crush. Numbers on these two were spot on, as have been all the others that were double crushed by NB.