Mysterious Efficiency Drop

[MrSnrub]

I know there are many threads on low efficiency on this forum, but my case is particularly odd. I've been using the same equipment (cooler + braid) and technique (single infusion 152-155F, batch sparge 175F) for over two years, producing around 50 batches. Until recently I got good efficiency, usually around 70% but sometimes as high as 75% or even 80%. For my past 8-10 batches, however, I've been lucky to get 60%, 50-55% being more typical.

I've investigated the typical culprits for low efficiency: my thermometer and hydrometer are properly calibrated, and I get my grain from Brewmaster's Warehouse, which has a reputation for a good crush. For my past few batches I've had them double-crush the grain to make sure this wasn't the issue, and still my efficiency has been poor.

Does anybody have some insight as to what might be going on?

 

[jdauria]

When you get the grain do you weigh it to make sure they sent you the right amount of grain?

Assuming everything else is the same, and your volume measurements are correct and your grain weight is correct, then I would look at your hydrometer or refractometer and recalibrate them again to see if they are off and you are getting the wrong gravity readings. Ditto with your thermometer to make sure your temps are right.

Another possibility, have you used more crystal malts or roasted malts that don't really add any fermentables with your last 8-10 batches?

 

[MrSnrub]

I have not weighed the grain, but I certainly hope they have not been shorting me!

My hydrometer reads .996 in water, so I add .004 to all my gravity readings. Thermometer reads 212 in boiling water, so I assume it's accurate at mash temperatures as well.

I have been brewing standard recipes, some of which I've done in the past with good efficiency.

 

[jarnock]

Do you have hard water? I took a significant drop in efficiency when my water softner was empty. Now I use springwater...

 

[mjohnson]

I also wonder about the water - I know that my city flushes the water system every March. Could your water source have changed? Maybe its messing with your mash pH. It seems like everything else you have is being controlled for.

 

[MrSnrub]

I live in Pittsburgh, which has soft water. I am not aware of any changes to the water source since I started brewing, but I will check my pH next time.

 

[CadillacAndy]

When did you notice the change? I'm also in the Pittsburgh area (Homestead/Munhall) and seem to have also had a drop in efficiency. My drop happened about 2-3 weeks ago.

 

[joyceman]

I live in Pittsburgh, which has soft water. I am not aware of any changes to the water source since I started brewing, but I will check my pH next time.

Are you talking about the water in the city proper or one of the suburban providers? Im on West View water but my understanding was that the PWA had relatively hard water.

 

[unitmonster]

Good luck trying to get any info from PWSA. I emailed them a few weeks ago and they gave me the phone # to someone in their lab. He never answers the phone (3x) and hasn't returned any calls. If anyone has a recent report, I would love to see it.

 

[MrSnrub]

I live in the city proper; I thought the water was soft since soap lathers up just fine, but maybe there's more to it. I think my efficiency first dropped about 3-4 months ago.

 

[joyceman]

9 times out of ten it seems like the answer is crush, but, like you said, BMW has a great rep. Nothings changed in your process? You havent started brewing all high grav beers and packing your mash tun?

 

[MrSnrub]

Same normal recipes I've always brewed. I just realized there is one thing that's changed recently: I replaced the braid in my mash tun and the new one is too long to lie flat on the bottom. But since the tun still drains just fine, I don't see how this could affect my gravity.

 

[joyceman]

Are you getting more dead space than before? Equipment loss can effect your efficiency.

 

[MrSnrub]

I don't see how that would happen, but I also don't know how to tell.

 

[ajf]

How do you calculate efficiency? With software like Beersmith?
If so, have you made any changes to the software?
I remember when I changed the boil off rate in Promash from a percentage to gallons per hour, it estimated a boil off rate at 15 gallons per hour.
I also had to reload Promash on my computer a few months ago, and since then my brewhouse efficiency has apparently increased by 15%. Next time I back up, I will reload the old image, and find out what settings I screwed up on the reload.

-a.

 

[m00se]

I experienced the same low efficiency with a recent purchase from BMW. I usually hit 76% efficiency on most of my brews resulting in a little higher ABV, but this weekend on a Rochefort 8 attempt I came in at 50% efficiency. I usually fly sparge, but didn't sparge with the same amount of water that I usually do. I'm assuming my sparge was the reason for the low efficiency. I really wanted that Rochefort clone to be 9% and not 6.5%.

 

[MrSnrub]

Could it be BMW? I did switch to them around when the efficiency drop happened; previously I had ordered from Austin. But I've read that they do a good crush, and I've even been asking them to double-crush the grains.

 

[m00se]

I brewed a day before the Rochefort clone with grains I crushed at my LHBS and had 76% efficiency. But I did Fly Sparge the day before.

 

[joyceman]

Maybe try a batch with grains crushed by Country Wines or South Hills Brew Supply. They generally give a decent crush. You can get a 10 lb bag of pilsen or maris otter for near online prices. At the least it will give you a baseline to measure against BMW.

 

[swackattack]

+1 on country wines. Great crush and with there prices and service little reason to go online