High Gravity Brewing at Home
A few big beers I’ve brewed over the years.
Oh, the joy of sipping a thick, robust stout. Or the warm, caramel complexity of an English barleywine. Or the sweet malty fruity aromas and flavors of a Belgian quad.
I’d avoided trying to brew big beers for a long time because of some of the horror stories I’d heard about brew days gone wrong – ending up with 6% barleywine, or aiming for 6 gallons and only getting 3, or the classic overstuffed and over-stuck mash tuns that refuse to cooperate.
Eventually I decided to take a swing - I’d read a little bit about high gravity brewing at home, but probably not enough. I am personally more of a hands-on, learn-my-lesson-the-hard-way type of brewer. I’m of the opinion that learning something from your own experience (and mistakes) gives you a much deeper and meaningful understanding of the task at hand, be it brewing or otherwise. The following is a a history of my high gravity brew attempts and what I’ve learned along the way.
First Stabs.
I can’t say too much about my first few attempts at big beer batches. I do remember vaguely that they seemed to come out with some combination of being thin bodied, uninspiring, low volume, and low gravity - never really more than 7 or 8% abv.
In recent times, I set out to really figure out the limits of my system and what it would take to brew a 5 gallon all-grain batch of 10% abv imperial stout or barleywine. I did not want to lean on any tricks or extracts – just wanted a baseline to build and improve upon, even if it meant -- worst case -- sacrificing a batch 😱.
Sometime in 2021, without much of a plan, I attempted an imperial stout. I simply packed my GrainFather G40 to the max (28 lbs of grain!), and pretty much just crossed my fingers and continued with my standard procedure. I was apalled to learn that my minimal preparation and half-assed effort did not pan out - instead of the potential 12%er that was printed on BrewersFriend recipe printout, I was looking at, at best, a 9% stout (some stout bois would call this a porter!). It was hard for me to accept the idea that for a batch that I had considerably more than double the amount of grain as, say, a 6% IPA, I was only getting 3% higher in abv.
Lesson 1 : Mash efficiency. The first major lesson I learned about brewing big beers is that mash efficiency starts to plummet as you go up in gravity. This is caused by a number of reasons, but in general, it helps to know this going into the effort. So, I stupidly did not even consider adjusting my standard mash efficiency for this brew. I typically get about 60-65% for most beers, sometimes higher for smaller beers. I consulted with award winning homebrewer and big beer guru William Spiesberger of James River Homebrew Club in Richmond, VA. He gave plenty of tips and advice, but what I remember most was that he mentioned that he goes into a big beer prepared to only get 50% efficiency. That was comforting because mine was in the 40s 😭
Lesson 2 : Mash Thickness. But knowing efficiency will suffer on big beer brew day does not address why. The next big problem with my stout brew was mash thickness (also sometimes referred to as water-to-grist or liquor-to-grist ratio). Although my G40 is quite big in general, the mash tun volume is actually not as spacious as I’d thought (technical note: the G40 is officially listed as having 11 gallons mash capacity and should support up to 28 lbs. Which is probably why I even attempted this in the first place. But anecdotally, this did not work out well for me). I remember the mash being really, super thick and almost dry in spots even after I stirred it thoroughly and had the recirculation going. On the homebrew scale, mash thickness ratio is tracked by quarts (water) : pounds (grain). Normally you’d want this ratio to be something like 1.25:1 or even better 1.5:1. For my brew, this was a flat 1:1. I’ve read that this is technically acceptable on the low end, but I will definitely not do it again.
Lesson 3 : Have extract on hand (and the correct kind). Depending on what your priorities for the batch are, you may want to have some (…or a lot) of malt extract on hand. If you are hell bent on your beer turning out above a certain abv, and/or want to be sure you get a full 5 gallon volume, you can supplement with malt extract towards the end of your brew day if you come out light. Stouts are nice because color is not so much of an issue. For barleywines or anything lighter, you will want to make sure the extract you use will only add gravity and no unintended colors or flavors (try Pilsen or light Pilsen if you can find it). One time I was brewing a NEIPA that came out light in original gravity, so I added whatever DME I had in the cabinet. It turned the beer orange.
Lesson/Option 4 : Boil the shit out of your wort* The next time I brewed barleywine, I was more prepared to battle low efficiency. I made adjustments to my water/grist ratio and also scaled my recipe up slightly for a bigger grain bill. But this time I set up my G40 to boil for 3 hours during family dinner and kid bedtime (electric brewing can be great for this kind of thing). The G40 and many electric systems these days have a 240v power source, which is great because you can sparge and collect a large volume of wort, then utilize the strength of the power source to boil off significant amount of volume to concentrate your wort. *This also comes with Maillard reactions (…caramelization) though, so be mindful. Some of this is expected in a stout or barleywine but there is a point where you can overdo it, scorch your wort, or produce astringent flavors.
This beer came out pretty damn good. It was a confirmed 10% abv and won a gold medal in a local homebrew competition.
The next year I brewed an imperial stout with this same procedure, but this time it was on my 115v Digiboil. Knowing it is less powerful than my G40 and would boil off less volume, I collected less wort to begin with, and combined my 3-hour boil time with my DME move (Option #3 above). When it finished, I confirmed it was a full 10.8% abv before sending into a barrel for 6 months. It came out fantastic. I think I am too greedy to send any bottles to competition.
Lesson / Option 5 : Collab with a buddy. One of the main issues with high gravity brewing at home is your asking you’re system to do something bigger and grander than it normally does. One way I tried to mitigate was by inviting a homebrew buddy over for a collab. Using two mash tuns instead of one, you have more mash volume and can combat water/grist ratio a little better. We lautered both mash tuns into a single boil. We chose not to sparge but rather to start with a bigger volume and take a single run from the mash tuns. For the boil, we used a single boil, but you could also consider splitting the wort into two boilers, which each would boil off more volume in the same amount of time than you would in a single kettle. When our Belgian Quad was finished, it was confirmed 10%, we aged it on rum soaked oak cubes for a couple months before canning the batch and splitting up the cans.
Lesson / Option 5 : Double Mash Personal research is great, but as a homebrewer it helps to build up a rolodex of brewing buddies, pro and amateur, that you can turn to for advice. Luckily I have a buddy who has recently gone pro, but still is quite connected and familiar with the homebrew scale. Darryl Puller is the head brewmaster with the CapSoul Brewing Collective, who I consider bonified master of brewing - particularly with regard to big beers (I like to refer to him as the “Stout King of Richmond” but the name has not caught on yet). Anyway, a while back he schooled me on his double mash technique. He fills his mash tun for a standard mash, lauter and sparge. This first mash produces only half of his eventual wort, so he begins boiling it while he cleans out the mash tun and resets it for a second mash. In this way you have two appropriately viscous mashes one after the other for max efficiency, and the first half of the wort gets a bit concentrated while the second mash is doing its thing.
Lesson / Option 6 : Reiterated mash. I’d heard of a perplexing idea of a “reiterated mash” from my my homebrew buddy Rob of @pixelperfectbrewing on Instagram. He said he added malt extract to his strike water, thus giving his batch a head start on gravity before even getting to the mash. This may effectively be the same as adding extract at the end, but could the same idea could be applied to all-grain…that is, can you produce bigger wort by using wort as strike water? Can you mash once, then use that wort as your strike water in another mash? Once consulting the web, it turns out, I was not the first to think of this.
I decided to give it a try. On paper this will obviously double the mash time, but 3-hour boils take a long time too.
A couple considerations – for mash #1, you will need to aim for more volume than you normally would since your wort from mash #1 will be your strike water for mash #2. This can be tricky to figure out where to start, considering the grain absorption losses from multiple mashes - it helps to work backwards. For my system, I knew to end up with 6.5 gallons of final wort going into boil kettle, I would need to start mash #2 with 8 gallons of wort-strike-water. That meant mash #1 would need to produce 8 gallons of wort, thus, I would need approximately 12 gallons of clean strike water going into mash #1. These numbers can change a little depending on whether you plan to sparge one or both mashes. I sparged mash #1 but only lautered mash #2.
In the name of having a somewhat controlled experiment (and since I’d spent all that extra time fooling with multiple back-to-back mashes) I decided no matter the result, I would not boil for my usual 3 hours, I ended up only boiling 75 minutes.
In the end, I had mixed emotions about the experiment, because the reiterated mash definitely did work, but it was only slightly better than my standard single mash + 3-hour boil. Next time, I could consider doing the reiterated mash and the 3-hour boil. It would just make a really long brew day.
At the time of this writing, I do not have any taste test results from this reiterated mash beer. It was an English barleywine that I threw into the barrel a couple weeks ago. I will look to rack it in 6 months or so and will update this article when its complete.
Conclusion. There are a lot of tricks and techniques to producing high gravity wort. I’ve tried a lot of them, and I’m sure there are more. At this point I’m happy that I have a couple plans that will produce top notch big beers, but I am still interested in exploring other twists that may improve efficiency and/or cut down time spent on brew day. What other techniques have you tried? Let me know in the comments.