Low efficiency out of nowhere

[sicktght311]

I've been using my 3v herms system for 3 years now. It was always extremely reliable and i could always build recipes on Brewers Friend with a 70% brewhouse efficiency in mind and i would usually come pretty close plus or minus depending on what grains i'm using. The last 6 brews i've done so far however have all come in VERY low in efficiency. For instance i brewed an IPA the other day with a target efficiency of 1.067 based on a 70% calculation, i ended up at 1.051. WAY off. Thats a 54% efficiency which is crazy.

Recipe was 10lbs Pilsner, 4lbs Flaked Oats, 2lbs Flaked Wheat. 6gallons finished batch size. 75 minute mash at 152 degrees. A recipe i've done before, and never missed the mark this wide. I have a mash tun with 2 gallons of dead space under the false bottom, but i recirculate so its not really dead space. Mashed in with about 5.75gallons, recirculated through the whole mash via herms coil, and Fly Sparged for about 45 minutes slowly until i reached by 7.25gallon preboil volume in the boil kettle. Final volume of 6.5gallons, of which around 6 end up in the fermenter leaving behind trub.

My efficiency problems started just before this, but when i brewed my pumpkin ale back in september and I had a horrible stuck mash, i ended up purchasing a brew bag to add to my mash tun to aid in filtering to avoid future stuck mashes when using high flaked grains like my latest brew, and to aid in cleaning. I still fly sparge, No change in process, so if anything the brew bag should help with efficiency since i'm able to recirculate a bit faster and not worry about clogging. I've tried crushing my grains to practically flour, i've tried backing the gap off a little bit to see if that changed things, but still i always come in super low. Before this IPA I attempted to brew an Imperial Stout which only had 5% Flaked Grains, and i was off by 15 gravity points, and that's AFTER adding 1lb of DME during the boil not included in my recipe to bump gravity assuming efficiency losses, even though i also sparged long enough to bring my preboil up for a 90 minute boil to try to maximize extraction.

So where am i going wrong for this to happen all of a sudden? I test my ph every few brews when i'm not feeling lazy, and its never been off from my target, and definitely not enough to account for this large of an efficiency miss.

 

[RM-MN]

I still fly sparge, No change in process, so if anything the brew bag should help with efficiency since i'm able to recirculate a bit faster and not worry about clogging.

That faster recirculation may start channeling. Slow it down again and see if you get improvement.

 

[bracconiere]

not sure if it matters...because i malt my own, but i've noticed a drop from 80% to 69% with the new brand of barley the feed store is carrying...

which makes me wonder, maybe there just isn't as much extractable sugar in it...?

 

[sibelman]

@sicktght31, is it possible your hydrometer has had some kind of incident? I've heard that sometimes the scale widget inside can slip a bit.

 

[bracconiere]

@sicktght31, is it possible your hydrometer has had some kind of incident? I've heard that sometimes the scale widget inside can slip a bit.

15 points would be one hell of a slip.....

 

[Jag75]

Your sparge doesn't appear to be to quick imo. Do you use rice hulls? As for your pumpkin ale issues I'm gonna go on a limb and say you added pumpkin puree to the mash. I did that once . Stuck like chuck let me tell you.

I would use hulls and I would slow down your mashing in by adding grain , mixing , adding more , mixing . Getting a good mix in before recirculating.

 

[sicktght311]

responding to replies here bullet point so its easier to follow

• Hydrometer isnt the issue. I have a tilt i use in the tank, and an analog regular hydrometer, and both match
• I only use a 25w Mark II pump, which isnt very high powered in the first place, so even when i set it to 50-60% open, its not really that strong. I wouldnt think it would be enough to cause channeling?
• When i dough in, i typically do as above. I add some grains until it piles on top of the liquid, stir, then add some more. Then i'll typically wait 5ish minutes while i'm dropping the temp of my HLT with cold water to bring my target down to mash temp, and then i start recirculating slow at first, gradually coming up to my target speed over a couple minutes.
• Yes i usually use lots of rice hulls if its something with adjuncts
• Hah yes, spot on regarding the pumpkin ale. The pureed pumpkin turns to concrete, so it was super stuck. Ended up just leaving it and the final beer ended up dry because of the temp loss during the mash, but it still turned out ok.
• Extractability wise, i've seen changes depending on brand of malts, but i typically account for that. If i use Viking Pilsner or 2-row vs Briess, i'll see 3-4% lower

 

[3 Dawg Night]

Mixing is huge. I don't recirculate, and I batch sparge, but one of my biggest efficiency hits came from the one time I forgot to stir after my sparge infusion.

 

[seatazzz]

Going to throw this out there because I just tried it last brew, and I got much better efficiency:

I use a mash bag as well; before last brew I just let it sit in folds on the bottom, and hoped my vigorous stirring with a big wire whisk got into all the nooks and crannies. I also underlet my strike water instead of adding the water to the tun first, then stirring in the grain. What I would suggest, for you, is fit your bag into your tun then dump the milled grain in it. Adjust the sides of the bag by pulling up until there is NO slack in the bottom, but it's not hanging, just sitting on the bottom. Fasten it there, then you can dump the grain out and fill your tun with hot water, and add your grain once you have that in. This way there are no little folds & caves for grain to hide from the strike water. I would also suggest stirring the mash a few times during the mash step. Residual dough balls are hard to detect when you dump out the spent grain unless you go through it meticulously.

If you have the means to do so, you can also try underletting; it takes a few tries to get it right, since the strike water needs to be just a smidge hotter, in my experience.