Author: Marshall Schott
Of all the process concerns/complaints I hear and read about when it comes to homebrewing, one seems to pop up more often than others: shitty efficiency. This typically takes 1 of 2 primary forms, either a brewer’s efficiency is lower than they want it to be or it is markedly inconsistent from batch to batch.
Before getting into the tips, it’s probably not a bad idea to understand what efficiency is. Kai Troester covers this topic well in an article on his website, I highly recommend you check it out for a more detailed explanation. In essence, mash (or conversion) efficiency refers simply to the amount of starch from the malt that ends up being converted to fermentable sugars during the mash, while brewhouse (or lautering) efficiency accounts for system losses that occur throughout the brewing process. The latter is what most brewers are referring to when they use the term efficiency and it’s what the focus of this article is.
For my initial 8 or so all grain batches, I experienced pretty drastic swings in efficiency, even for styles similar in OG. Not only had I been having my grains crushed for me, but I was purchasing ingredients from a few different homebrew shops. Fed up with this inconsistency, I began researching how I might remedy these issues and started paying closer attention to certain elements that were potentially having an impact. What follows is a list of things I’ve done that have helped increase and stabilize my efficiency.
1 | Stop Worrying About Efficiency
One perspective when it comes to dealing with the woes of low efficiency, definitely the simplest to employ, is to accept it for what it is and compensate by using a touch more grain. I personally think this is a good option for those who don’t want to, or can’t, purchase more equipment, particularly if efficiency is consistently around 65%, as the cost for the compensatory grain is usually negligible. While there seems to be a sect of brewers who pride themselves on super high efficiency, the beer they make fares no better than the brewer getting less efficiency. It’s a banal competition that distracts from the real focus of brewing, which is making good beer. In fact, some contend the quest to eek out a few extra gravity points may actually decrease wort and, consequently, beer quality. Using software such as BeerSmith, any brewer can setup their equipment profile to account for their particular efficiency, which then automatically compensates when designing a recipe.
2 | Mill Your Own Grain
Probably the most popular first recommendation to a person complaining of poor efficiency is to acquire a grain mill, which is good advice for a number of reasons. Owning your own mill allows you to precisely dial in your preferred crush by changing the gap between the rollers, with certain mash methods having different requirements. Moreover, personal grain mills are usually used by a single person far less frequently than a mill in a shop, meaning it maintains its settings much longer, thereby improving the consistency of efficiency. I received my first mill, a Barley Crusher with 15 lbs hopper, as a gift a few years ago and even without messing with the factory gap setting, I experienced a bump in my efficiency from 67% to 74%; after tightening the gap to 0.030″ (the thickness of a credit card), my efficiency maintained a stable 78-80% depending on my target OG.
A great addition to my brewery, to be sure, the Barley Crusher took good care of me for quite awhile. However, given the frequency with which I brew and the fact I regularly mill enough grains for 10+ gallons of beer, I began searching for a heftier option and eventually settled on the Monster Mill MM3, a 3-roller rig that has so far impressed the hell out of me.
If you’re looking to upgrade or prefer purchasing items to grow into, I can’t recommend this mill enough, it kicks more ass than Van Damme at Kumite. I think many brewers would agree that adding a mill to their pile of gear contributed more than anything else to improving efficiency and consistency in their brewing. It also makes bulk grain purchases an option, which is a huge money saver.
3 | Stir The Mash
It was probably 4 years ago or so when I read something somewhere about someone regularly achieving 78-80% efficiency using the batch sparge method. Among the myriad responses as to how this might be possible, the dude mentioned he stirred his mash 2-3 times throughout the 1 hour rest. I employed this simple technique on my next brew day, opening the lid just a crack to stir the mash for maybe 3-5 seconds every 15 minutes. And it worked! I had consistently been hitting 70-74% efficiency, though this batch clocked in at 78%, a result I’ve since replicated many times.
Some people might be concerned about the heat lost during this process, something I was curious about when I first started stirring mid-mash. Even during the cooler months, the most I’ve observed the temp drop is 4°F over a 1 hour mash rest, though it’s usually only about 1-2°F. Despite what we know about the enzymatic action that occurs as a function of mash temperature, I’ve yet to notice any degradation in my beers as a result of the loss of a few degrees, and they continue to finish at my target FG. Another concern a very small number of folks have expressed is increased tannin extraction due to mash agitation, something I’m becoming more and more convinced is a general non-issue on the homebrew scale.
4 | Accurately Measure Your Losses
As mentioned earlier, brewhouse/lautering efficiency takes into account much more than just the amount of sugar extracted from the grain. As such, it stands that miscalculations in the shit that gets calculated into brewhouse efficiency will have an impact on the overall percentage. Boiloff rate, MLT deadspace, kettle loss, trub loss. All of this need to be measured with some degree of precision in order to get the most accurate brewhouse efficiency so that you hit the numbers you expect. For example, if you assume a boiloff rate of 1 gallon/hour yet regularly end up with a gallon less wort than expected, your brewhouse efficiency is going to suffer, even if you’re getting high extract efficiency. Simply taking note of the amount of wort boiled off over an hour then plugging that into your brewing software will improve your efficiency. This holds true for the other factors mentioned as well. Precisely dialing in your equipment profile will allow you to trust the predicitons of you recipe calculator and thereby improve your overall brewing consistency.
5 | Try A Different Approach
Some people are married to their brewing method, refusing to consider anything that ventures outside of what they’ve accepted to be the best approach. It’s always sort of interesting to me when these folks seek assistance on something like improving efficiency, then shoot down any suggestions to tweak their method. What works for one may not work for another is an adage I fully agree with, I think the keyword though is “works.” If you’re not achieving the results you so desire, perhaps your process isn’t necessarily working for you and hence trying something different might be the ticket. I’ve heard positive stories from fly spargers who transitioned to batch sparge, batch spargers who went to BIAB, and BIAB’rs who switched to fly sparge. Different strokes for different folks. The key is messing around until you find what works best for you.
6 | Maybe It’s The Malt?
A few months back, I made a batch that came in 0.006 SG points lower than expected, dropping my typical 78% efficiency by nearly 10%. I double-checked my mill gap, made sure to stir the mash 4 times before running off, and ensured my mash pH was on point for the next batch, yet my efficiency was still coming in way lower than target. I then did what any self-respecting homebrewer does in such situations and bitched about it to my buddies, a few who reported they’d been experiencing the same thing. As we began troubleshooting, we realized the one thing we all had in common is that we’d each recently purchased a sack of 2-row from the same maltster. To test this theory, I brewed a batch using base malt from a different supplier and, voila, my numbers were right on target. Likewise, when I switch between standard 2-row and pilsner malts, I notice a 3-4% difference in efficiency, so I have a few profiles setup in BeerSmith to account for this.
| CONCLUSIONS |
Efficiency is one of those things homebrewers seem to fret over a bit more than they need to, with some apparently viewing it as a representation of their brewing prowess. Honestly, if you are consistently achieving 65%+ efficiency, consider yourself golden and focus your attention on something else. For those regularly getting very low or inconsistent efficiency, I might recommend first double-checking the settings in whatever recipe calculator you use to make sure your losses are accurate, and if that’s all good, consider picking up (or borrowing) a grain mill. If you happen to notice a change in efficiency only after using a new grain, it’s possible that’s the culprit. Ultimately, by utilizing some of the tips above, you should be able to dial-in your efficiency well enough so that your regularly able to hit the numbers you expect.
There is a method I’ve seen discussed quite extensively that appears to have little if any impact on efficiency: double milling grain. In theory, this seems like a good idea, running grain through a mill multiple times to get a finer crush. But practically, this doesn’t seem to be the case, the small previously milled bits of grain simply fall through the gaps. It’s possible slightly more grains get crushed, but in my experience, it doesn’t have nearly the impact on efficiency as reducing the gap between the rollers. Also, for whatever reason, many homebrew shops aren’t comfortable running grain through their mills more than once.
If you have any thoughts about improving efficiency, please do not hesitate to share in the comments section below!
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43 thoughts on “6 Tips for Dealing with Efficiency Problems”
Great article. IMO, if your efficiency is consistent you’re doing well. With consistent efficiency you can hit your numbers on brewday, and thus achieve the beer you want.
Most of the people i know will happily add an extra 1-2 hour to their brewing day via sparging and lautering and not using a bag, multi-rest mash etc. in exchange for like 1$ in grain. I can’t understand them.
Yeesh…
About one every three or four brews, I will hit my SG on the head. The other 75% of the time, I am off by .002 higher or lower. To me, that’s good enough.
To your point about malt, though. Recently, I’ve done a couple brews using Rahr Pale Ale malt, and both times I was off by a wider margin. .006 one time, and .007 the other. I don’t have this problem with their 2-row (or any other malt, for that matter), but I swear there is something about their PA malt that throws a wrench into my efficiency. I read somewhere that the kernel size of Rahr PA malt can be inconsistent, potentially causing a bad crush, but that could be total internet bullshit. Still, I’ll be shying away from that malt in the future.
I believe Pale Ale Malt has a lower diastatic power than 2-Row or Pilsner Malt.
I’ve been adding another half pound or so of the base malt when I brew and consistently hit my OG target gravity. What’s it cost, like a dollar? I guess I’m firmly in the ‘don’t worry about efficiency’ category for now.
Nice! If you account for that in your brewing software, you won’t have to add any “extra” malt, as it will simply calculate things accurately for you.
Agree! And also it is insanely easy to hit your OG if you hit a number above it: just add a bit of water in the last 15 mins of the boil.
So basically you can always hit your target if you are a bit pessimistic about your efficiency.
I used to hit 65-70% efficiency batch sparging. I got my own grain mill and it went to ~75%. I started stirring the mash 3 times over the course of an hour like you do and it went up a few more points to ~78%. Finally, I started taking almost an hour to sparge, 1 qt./minute for 10 gallon batches, and my efficiency shot up to ~85%. (I used to drain as fast as I could without getting a stuck sparge.) Whether all that effort is worth the price of a few pounds of grain, I don’t know.
Dammit. That should say ‘fly sparging’.
Personally, shorter brew days are worth the slight hit to efficiency.
Great tips. I’m only on my fourth AG so I’m still dialing in my process, but I keep tweaking one piece of the puzzle each brew day. It’s slowly increasing my efficiency from 58% on my first batch up to 66% on my latest. I was always afraid to stir too much and lose heat so I’ve only been stirring once halfway through. I’ll have to try stirring more often next time.
The only problem with constantly tweaking and increasing efficiency is overshooting my OG and making bigger than expected beers. Or maybe it’s not a problem. 🙂
I BIAB and stir my mash A LOT. I stir every 10 minutes or so. There’s really not much heat loss each time I stir. Most heat loss comes from loss through the sides of the mash tun. Plus I usually keep my burner on low when I mash. I check temp each time I stir. As for getting too high an OG, well that’s usually a good thing because I tend to experience underperformance with yeast.
Plus by the time I’d need to do the efficiency calc I’m pretty drunk 😉
Another thing to think about is that malt batches can vary from bag to bag, season to season. If the Briess 2 row was great this season, it could be a little lower in starches next year. Like grapes, some years and areas just produce a better product.
I recently picked up a Cereal Killer grain mill and used it this past weekend for the first time, to “double” mill grains for a pumpkin stout. My efficiency definitely went up, however either the finer grains and/or the canned pumpkin made it a bitch to squeeze out as much wort as possible from my bag.
So that brings up my question… I set my mill to the width of a credit card, which is what I’ve most frequently seen recommended. I only ran the grain thru once, but I ordered the grain online and chose to have it milled, hence the “double” milling. So my question is for people who mill their own grains, when purchasing online or from your local shop, do you also have it milled there? Or do you buy whole and mill it once (or twice) yourself? As it stands now I’m afraid the credit card width may lead to too fine a mill, but that could also be due to the grain having been milled once before.
I buy base grains by the sack and specialty malts in 10 lbs increments, unmilled because it’s purported to stay fresh longer. A mill gap of 0.030″ (credit card) works perfect for all barley malt grists using the popular SS braid manifolds; however, greater percentages of huskless malts with high beta glucan content (like rye) can definitely impact lautering. How do you mash? You can always snag a quality BIAB bag, which makes lautering pretty much anything super easy!
That’s the exact bag I use, in my 15 gallon kettle. I couldn’t agree more about the quality!
I typically just mash for 1 hour in my kettle, wrapped in a couple layers of Infra-Stop insulation. Then mashout for 10 minutes @ 170°, then squeeze the hell out of the bag til my arms are numb. No sparging or anything.
Now that I know my grain mill actually works (and works well at that) I’ll probably start ordering grains whole. I too have heard it’s best to keep whole until you’re ready to brew.
I used to hit 76-80% or so in a 5 gallon water cooler MLT. Obviously that is kinda small so I switched to a bigger cooler and now I piddle around 68%. I have tried stirring, raising sparge water a few degrees, spending more time making sure I get the wort out of the dead space (below the valve). I just can’t get my efficiency up in this cooler, so I changed my software and just complain about it to myself sometimes.
68% is fine!
once I set my mill to a smaller crush and started mashing for 90 minutes and stirring three or four times during the mash process my efficiency went from 68% to around 72% and I am fine with that. My beer seems to taste ok and most people who drink it seem to agree with me.
I’ve compared different mash lengths, only 1 has been a formal xBmt, but I’ve not noticed it having any significant impact on efficiency. Definitely need to do a few more!
Once you have achieved conversion, increasing mash length will not improve efficiency. It will increase fermentability.
Increasing the liquor/grist ratio improved my efficiency considerably. I find no benefit to stirring during the mash. I average 83-85% efficiency without stirring.
I’ve always been surprised with your efficiency numbers, I only hit 83% on my setup when using mostly Pils base malt, regardless of my liquor:grist ratio. What’s your mill gap set to?
Great guidance as always. It took me way too long to realize your #1 tip and consequently I kept screwing around with my process every batch to try and hit 80+ percent. Once I realized efficiency consistency is way more important than squeezing the most sugar out of the grains, my brewdays were better and, not shockingly, my beer was better too. I spent way too much time and $$ adjusting hop schedules mid boil or adding DME late to make up for wildly varying mash efficiency. I hope this article helps others avoid my pain.
A big +1 to stirring the mash. Adding 1-2 stirs per mash has moved me from 60% ro 68% reliably.
Great article. I’ve been steadily honing down my brew day based on info from this site; 45min mash with BIAB, 30min boil, usually wrapped up in 2.5hrs, and at around 68% brew-house efficiency I’m happy considering grain is cheap. I noticed you didn’t mention water treatment, ie pH adjustment as a contributing factor, have you found this also has an impact on efficiency?
Some people swear water chem has an impact on extraction and overall efficiency. Personally, I have not found this to be the case.
Sweet article. I couldn’t agree more with your tips and advice. I use brewsmith to calculate everything. I mill my own grains, stir the mash every 20 min, and my efficiency is almost always in the 78% range. Couldn’t be happier. I brew so much that nowadays I’m not even that concerned with efficiency or SG. I mean, my friends and I are going to drink it all anyways. It’s more about what the beer tastes like at the end. I’m more concerned with sanitary practices to make sure it’s all good during fermentation and packaging.
My efficency was dropping and I was compensating and it was OK. THen I realized my thermometer was way off. The fancy digital one had gotten wonked and was teading 20 degrees low. Replaced that and Bam the wort was way over what I expected. So not exactly a “tip” but checking the devices you use to mesure things every once in awhile can save some pain.
Regularly checking the calibration of measuring devices is key to ensuring accurate numbers. I have a buddy who experienced a very similar problem.
Just had a bummer brew day. Ended up missing target OG by .017. 🙁 Did a couple things differently, now I’m not sure what (or what combination of things) led to such a disappointing result. This beer is going to be a mess, I’m afraid.
I bet it’ll be fine 😉
What kind of variation in yield is typical for grains? How much of it varies from batch to batch vs. loss of yield due to age? You saw a loss of 0.006 points, is this typical?
I really have no clue.
Do you have any issue with temperature drop while you stir during your mash?
I’m sure it drops a bit, maybe 1-4F depending on outside temp… but it’s never been an issue for me.
I used to get around 65-70% efficiency but I’m up to 80-85% now thanks to a few changes. Some of them are very simple, others are more radical. In order of simplicity:
* Allow more of the post-boil trub to tip into the FV. It won’t do any harm (refer to Brulosophy experiment on trub)
* If you use a coolbox mashtun, before you start collecting runnings prop a book or two under the back end to tip the coolbox so there’s less deadspace under the outlet level.
* Don’t tip grain into the mashtun quickly – it will form doughballs. Rain it in slowly, stirring as you go. Give it a good stir before you put the lid on.
* Mash thin. Use at least 3/4 of your total liquor volume in the mash. Use the remaining water for a short batch sparge. This will shorten your brew day a lot. After sparging, drain the runnings slowly.
* Mash overnight. As well as shortening the brew day dramatically and raising efficiency, this will give very good extraction from coarsely milled grain. You need to keep the temp up if you mash overnight, so an insulated tun is essential and extra blanket or two doesn’t hurt. Use a large mash liquor volume for for high thermal mass, which maintains temperature better.
I thought it was interesting that you mentioned not worrying about efficiency. My brother is looking to get mechanical milling supplies but needs tips. i’ll be sure to talk to him about not worrying about the efficiency. http://www.alliedhightech.com/equipment/mechanical-milling
I use a “Magic Bullet” to pulverize the Christ out of my grain into almost a flour consistency, and also use a 90 minute BIAB mash, and have been hitting the low 80’s for about the last 10 batches. I wonder if a shorter mash would lower my efficiency?
Hi Marshall, you mentioned in the podcast that you keep four grains on hand plus some specialty grains. What do you find to be the must-haves, or most versatile to have on hand?
Pale malt, Pilsner malt, Maris Otter, and Vienna malt. I also like to keep smaller amounts of C40 or C60, Pale Chocolate, Honey malt, and Roasted Barley on-hand.
I have had to swap suppliers of my grain and I am doing nothing different but I am only getting beers at .04% when they should be 5-6%. I have now brought salts to start messing with water chemistry I hope this fixes it. thanks for the comments above they confirm what I have been thinking