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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