AG Efficiency just took a dump on the last batch

[924RACR]

Here's a weird one, curious to see what the group thinks.

Making our IPA recipe... have made it numerous times, just down to tweaking hops at this point:
20# 2 row
3# 10L
4oz Carapils

10.5gal target into fermenter with 60min mash @150, 60min boil, 12gal pre-boil volume. 1.056 pre-boil SG, 1.064 OG into the fermenter.

Rig is keggles, with a false bottom and dip tube in the mash tun. Normally we're pushing 80% eff with the fly sparge.

Grain is milled at Adventures in Homebrewing, but then we run it through our own at home (double crush) to be sure. So crush was good.

This time we had a split of 1.5# fresh Carapils, 1.5# that had been sitting around in a plastic bag, cool storage since around March. All 2-row was fresh.

Mash-in was perfect on-target, 7.25gal plus 2gal for the false bottom. Hit our temp within a degree and stayed there.

Didn't bother to check pH, as it's usually in the zone with this recipe, plus we don't have super-accurate pH strips.

When we got to sparging... needed 8 gal to sparge, but our hot liquor tank is only comfortable with 6.5gal. So we heated 2 gal separate, started by dumping those in and stirring... then vorlauf (ran clear pretty quickly after 1-1.5gal), then right into the normal fly sparge.

But right off the get-go, the numbers were low, started at only 1.056SG right out the tube to begin with, and dropped from there (of course). Actual OG measured was only 1.051 - about 64% efficiency. Will still make decent beer, but a touch thin...

So I want to redo that batch and try to rectify that process error.

My culprits right now for the source of the loss of efficiency...

#1 thought is our goofy partial-batch-sparge process. Might be messing up the high efficiency we should get from a proper fly sparge. Plus I seem to recall that when we were pumping out 80% batches, we were making 5gal batches... which didn't have HLT volume issues.

#2 - maybe my mash is too wet? This would kinda make more sense to me in terms of just poor conversion efficiency, even before the sparge happens... plus I think some of those earlier high-eff 5gal batches mashed in on the dry side, perhaps closer to 1.10 qts/lb?

Any other ideas? As mentioned, I think we'll try this one again, with more careful attention to the above two steps, and see how it goes...

 

[mjohnson]

Maybe dough balls. Even small ones can add up. I like to mash thinner for this reason.

 

[stonebrewer]

When I make Arrogant Bastard, which is a few more pounds of grain than your recipe, I mash with 9 gallons and hit around 1.070 pre-boil. Similar grain bill to yours. Suspect you are mashing with too much water. My efficiency was 78.6% on the AB clone...

 

[924RACR]

Thanks... definitely sure there were no dough balls on this batch; we add the grain to the water in the mash tun with extensive stirring... I can personally vouch it was good...

Likely will take 1gal of water out of the next round, see where that puts us...

 

[RM-MN]

#2 - maybe my mash is too wet? This would kinda make more sense to me in terms of just poor conversion efficiency, even before the sparge happens... plus I think some of those earlier high-eff 5gal batches mashed in on the dry side, perhaps closer to 1.10 qts/lb?

Maybe your mash was too dry. I BIAB in nearly the full volume of water, about 2 1/2 qts per pound and get full conversion and great efficiency, about 80% with no sparge or 85% or better with a very small sparge.

 

[924RACR]

Update on this... did another ale Sunday, this time a Chocolate RyePA... of course not the same recipe, but similar mash and setup.

No issues this time, despite being a bit low on mash temp (overestimated the temp of the grain and tun). Efficiency was back dead-nuts on 80%.

Only difference was we remembered to verify the setting on our mill; it had in fact slipped slightly at one end, so we did get 'er tightened back up. That said... we are getting our grain pre-milled, so our milling step is a second run through.

So... as much likely to be an issue of old grain, or that excessive watering before vorlaufing and sparge, as the milling gap.

But at least we're back where we should be. Looking forward to trying that RyePA in a month or so when she's ready...

Next up, I think another 10gal of Old Chub...

 

[kh54s10]

I would lean toward the crush, though it should not have been too bad with just the original crush from AIH. Or the amount of water or sparging technique.

Unless your older grain was not well stored I doubt that would cause a big problem. I store both base and specialty grains, most for at least as long as you stated. I don't see much change in efficiency when using new as opposed to stored grains.