Big Batch BIAB

It seemed like a normal weekend brew day amongst friends. As the first ray of the rising sun hit the shiny stainless exterior of the 30-gallon (113-L) kettle sitting in the driveway, the burner was lit and flames began to lick the bottom of the kettle. We’d soon be mashing in with over 75 lbs. (34 kg) of freshly milled grain. The water reached strike temperature, and the age-old tradition of mixing grain with water to make wort commenced. An hour or so later, as the neighborhood began to wake up, parents drove their kids to soccer, joggers ran by, and dogs were walked. For some reason all their heads were turned as they passed my house. Perhaps it was the new paint color on the door or the way we had manicured the shrubs. Or maybe it was the larger than life, dripping mesh sack hanging six feet high from a telescoping ladder that caught their attention. This was no ordinary brew day, this was a Mega brew-in-a-bag (BIAB) brew day.

To understand how we got to this point of the story, we need to rewind a bit. For years, in fact for nearly my whole homebrewing “career,” I have used the all-grain BIAB technique. This technique uses a fine mesh bag to consolidate the process and amount of equipment brewers have traditionally used to brew all-grain beer. Now, I’m not necessarily lazy (alright, maybe a little), but whenever I have a chance to reduce equipment and shorten a process, and still end up with fantastic results, I’m in.

Let’s talk results; I often see forum posts that go something like: “Look guys, I won a ribbon with this BIAB beer. Who says you can’t brew good beer using BIAB!” There’s been some kind of perception in the past that BIAB is simply an on-ramp to all-grain brewing. I feel that the perception has slowly been changing, but now that I have the stage, I can offer my own experience: Every single award I have won for a beer in competition was spawn from the BIAB technique. For example, in last year’s National Homebrew Competition, the largest homebrew competition in the world, I had a BIAB beer that received a Gold Certificate (Earned by entries scoring 38–50 points in the first round). It should come as no surprise then, that when I started to get the inkling to create a large batch brewing setup, that I was hesitant to do anything besides BIAB. But, was large batch BIAB even possible?

When thinking of large batch homebrew setups, many of us imagine three massive kettles, multiple burners (or elements), and pumps to move the beer from kettle to kettle. The prohibitive price tag and space requirements quickly squash those dreams, and we stick to our 1-, 3- or 5-gallon (4-, 11-. or 19-L) batches. I had those same reservations, and am here to tell you there’s another way. Drum roll please . . . it’s what I’ve termed “Mega BIAB.”

But wait, isn’t BIAB only good for doing little batches on your stovetop? Absolutely not! BIAB, whether on a small or large scale, is not only a legit way to brew potentially world-class beer, I’d argue it can be a far better way to brew beer. A Mega BIAB setup requires a single large kettle and burner and that right there is far less equipment than a 3-vessel system requires. There will be no 3-tier brew stand around here! A well-planned Mega BIAB setup also doesn’t require a single pump. In addition to the massive cost savings, doing large-batch BIAB can speed up the brew day, simplify the process, and certainly makes for less cleaning too! Sounds good, but what do you need to put together your own Mega BIAB setup?


One of the first things you’ll need to determine is what size BIAB batches you’d like to do. This will dictate kettle size, and multiple other factors are based off of this. I chose a 30-gallon (113-L) Spike kettle, which allows me to host “Vermont Experimental Brew Crew” brews at my house with some of my brew buddies from Vermont’s Green Mountain Mashers Homebrew Club. We typically net around 24 finished gallons (91 L) of wort using the 30-gallon kettle. If we use an anti-foam agent like Fermcap-S in the kettle, we can increase the volume a little. Each participant can take a share of the wort, or we can ferment it all in bulk and fill a fresh 15- to 25-gallon (57- or 95-L) oak barrel sourced straight from one of our local Vermont distilleries or maple sugarhouses. Once you determine the size batch you’d like to make, and have purchased a kettle, take width and height measurements of it. You will need these to obtain a proper fitting mesh bag.

The mesh bag is the star of the show in your BIAB setup. This is not a piece of gear that you should skimp on. There are a couple manufacturers out there making high-quality mesh bags for BIAB. I recommend you seek out a company that sells bags made of Voile. I’ve been using bags custom sized for my kettle made by The Brew Bag with great success. The bags are made of strong Voile mesh material, have extremely sturdy straps sewn on, and easily handled the 155+ lbs. (70+ kg) of grain and absorbed liquid we threw at it on an imperial stout brew day. According to The Brew Bag website, “Voile has a threads per inch count of between 85 and 95 (about twice what a nylon paint strainer bag has). It is made of polyester, does not stretch, and is very strong.” There are other bags out there made of lower cost material that could work for your rig, however after seeing one easily rip open on a thermowell (it looked like a bullet hole), I caution you to tread carefully. When you order your bag, you will need those kettle dimensions you recorded to ensure you get a bag that nicely fits your rig. You don’t want a bag that is too small or a bag that is too large for your kettle.

Next, you’ll need a burner that can handle the weight of your kettle filled with liquid. If you’d like to go pumpless, you also will need to have the kettle high enough so that you can use gravity to fill your fermenters from the kettle’s ball valve. You will either need to get a burner with a tall stand or you will need to put a shorter stand up on something sturdy, such as concrete blocks. Note that the higher your kettle is, the taller your BIAB hoist’s anchor point needs to be. If you go pumpless, I recommend getting an immersion chiller appropriately sized for the batch volume you are doing. For 20- to 30-gallon (76- to 113-L) batches, I’m using the JaDeD Hydra with good success. When I brew with friends, we usually stick the chiller in and take turns stirring the wort around it with a mash paddle. Using an immersion chiller really makes the chilling process simple, and there’s something special about using muscle and paddle to make beer. However stirring for 15+ minutes can be tiring, so if you already have a pump laying around, you could use it to whirlpool the wort around the chiller and save yourself the hard labor.

To do Mega BIAB, you will need a strong anchor point. For my setup (pictured at left), I use a tall ladder with a 2 x 6 secured across the top. A stainless steel screw eye with a 250-lb. (13-kg) rating is screwed into the center of the 2 x 6. The ladder straddles the brew kettle and needs to open wide enough to accommodate the width of the kettle and burner. The ladder also needs to be tall enough to allow the bag to be lifted completely out of the kettle after the mash. The ladder I use (a 22-foot/6.7 m telescoping multi-position ladder, set in “step-ladder” position) gets the screw eye around 8.5 feet (2.6 m) off the ground. I would prefer a slightly taller ladder, since my bag still hangs in my kettle a little when fully hoisted up, but it is very close to perfect for me. My ladder is rated for 300 lbs. (136 kg). All of these weight ratings are important — you are hoisting something hot and heavy into the air, so make sure every single component you use can handle the weight of a grain bag that has fully absorbed liquid.

There are a variety of other anchor point options I’ve seen used including a hunter’s deer tripod and the rafters of a garage. Perhaps my favorite is my friend Dan Welch’s setup that includes scaffolding on wheels. The scaffolding accommodates both our large kettles and burners side-by-side (as pictured at the top of this article) allowing us to easily brew enough in one session together to fill both our 15- and 25-gallon (76- and 113-L) oak barrels. Once we finish the mash and pull the bags, the scaffolding simply wheels away. Dan had the scaffolding already, so it made perfect sense to use it. Similarly, you may already have something that would work for your anchor point too, so look around, and don’t forget it needs to be high enough and sturdy enough to do the job. (While my ladder does the job, my dream anchor point rig is a 1-ton Telescoping Gantry Crane with a Push Beam Trolley — look it up! I’m convinced I could easily run a small brewery with one.)

London-based homebrewer Richard Conroy provided additional advice, “You need a way to lift the bag out of the kettle, and have it drip drain into something. Ideally without mess, but this operation needs to be safe and reliable. If you can brew beneath a load-bearing anchor point, like a sky hook, an upstairs bannister rail, a shed cross beam, or a wall cleat, then this box is ticked. If you need to improvise a portable or DIY anchor point, like a ladder, A-frame, tripod or bicycle mount, ensure it is secure.”

Next, you will need some sort of hoist to help you lift and suspend your bag filled with wet grain. There’s a variety of tools that can be used to hoist the heavy grain sack up and out of the kettle once the mash is complete. Which tool you choose will depend on the size of your muscles and the size of your budget. A rope and pulley is perhaps the simplest and lowest cost method. I started using a basic low-cost ratchet pulley for smaller BIAB batches, and then graduated to a slightly fancier 2:1 ratio pulley for larger batches. I quickly learned though that even with the 2:1 ratio, vertically lifting bags that weigh over 100 lbs. (45 kg) was more challenging than expected. I then upgraded to a powered portable hoist with a 1,000-lb. (453-kg) capacity, which has really made Mega BIAB brew days easy. I’m now able to effortlessly lift the bag out of the kettle by simply pressing a button. I had considered using a chain hoist, however didn’t like the fact that most of them have oil all over the chains. The electric push-button hoists are usually the most expensive option, and typically cost between $100-150. Colorado Brewing Systems builds brew systems for professional breweries, and their larger single-vessel rigs, which employ a hefty stainless perforated bottom “mash basket” (instead of a BIAB mesh bag), have the electric hoists, while some of their smaller rigs have rope pulleys. I’d say that if you are budget-conscious and well-muscled, try out a rope pulley first, but know that for less than the price of a nice pump, you can upgrade to “press-a-button” level of easiness.

Speaking of muscle, you may be able to physically lift the bag vertically up out of the kettle and onto your anchor point without using a hoist, as I’ve heard from at least one fellow homebrewer who does.

Benefits for Pros and Homebrew Clubs

Worth noting is that doing large-batch single-vessel brewing is in fact something that is being done on a professional level. One of the main differences I see when comparing these pro systems to BIAB is that they nearly always use a large stainless steel basket in place of a mesh bag. I would think the stainless basket would last indefinitely, but the tradeoff would be cost versus the mesh bag. The pro systems almost always have some form of mash recirculation too, which is possible to do on a homebrew scale, but not critical (personal opinion). The popularity of this single-vessel style of brewing seems to be growing for new, smaller breweries, as the cost to start is low versus a 3-vessel setup, and the process is simplified, with the same high-quality end results. I personally know multiple breweries that opened over the past year that are using this type of system. Matt Shortway, managing director of Shortway Brewing Company in Newport, North Carolina uses Colorado Brewing System’s 5-BBL MicroBrewer Pro. Shortway said his team was able to create an incredible manufacturing facility with taproom and beer garden for a fraction of the price (compared to other breweries) thanks to the benefits of using a professional single vessel system such as this. Shortway mentioned that he couldn’t be more pleased with the very small footprint, reduction of brew day time, and high brewhouse efficiencies (between 85-94%) he gets with the system. After hearing and seeing plenty of smaller breweries having such positive experiences like this with single vessel, it further solidifies my belief that a single-vessel technique like Mega BIAB is an excellent way to brew at home.

It also is a fantastic way to add capacity to your homebrew clubs’ system. I’m currently working with the Green Mountain Mashers to add a 60-gallon (227-L) Mega BIAB setup to our current 3-vessel club system space. We will be doubling our wort-making capacity with this new addition, and all of the gear needed was already owned or donated to the club.

Club President Jason Stuffle added, “Once complete we’ll have the ability to do club social brews up to 3 barrels or high gravity 1.5-barrel brews when combining systems. The club is looking forward to trying some ‘stuck mash’ type beers [100% wheat] on the Mega BIAB and it will really help for a simplified setup for intro to brewing type classes since we can run this without a HLT/sparge, pumps, or transfers. We can focus on the brewing and add other equipment as people advance. The custom brew bag fits all four vessels in our system allowing for multiple brewing configurations that can be set up to best match the needs of that brew.”

Brew Day Process

Now that we have covered the important gear you’ll need to do Mega BIAB (short list, eh?), and how advantageous the technique is, let’s talk about what a typical brew-day process would look like. I can describe the process on my system, but yours will vary slightly depending on the gear you choose to employ. We’ll only focus on the specific Mega BIAB-related process here. First, the burner and kettle are set up in your desired brewing location. The kettle is filled with strike water and the burner is turned on. While the water is heating up, you can configure your anchor point and hoist setup. For me, this means setting up my ladder so it straddles the kettle, securing the wood plank that has the anchor point across the top of the ladder, and hooking up my hoist to the anchor point so that it is ready to lift the bag when the time comes.

Once the strike water has reached temperature, put your mesh bag in the kettle and clip it to the rim so that it doesn’t fall in during mash-in. Add milled grains slowly to the kettle and stir. Note that when doing the BIAB technique, you can finely mill your grains without the fear of a stuck mash, which can greatly improve your efficiency. Once all the grain is incorporated into the water, put the lid on and insulate the kettle. I cut out a “jacket” for my kettle using Reflectix material and adhered some Velcro tape to the Reflectix so it can be easily put on and taken off the kettle.

When it is time to pull the grains, I hook the mesh bag to the hoist and slowly lift the bag out of the kettle, giving time to allow the bag to drain into the kettle. Many people who do BIAB do not sparge and simply move on to the boil. However, if you would like to, you can sparge the bag by pouring water over the top of the grain bed within the bag, or do like I do and trickle water from a hose (run through a carbon filter) over the top. The goal is that you want the sparge water to be flowing all the way through the grain bed, rinsing out valuable sugars, and not just along the sides of the bag, so closely monitor the process. I am a big fan of cold water sparging as I get the benefits of sparging without needing an additional kettle to heat sparge water to 168 °F (76 °C). I’ve personally had amazing results with cold water sparging and love the technique. Some brewers also squeeze the bag to extract more liquid from the grain.

The last piece of the puzzle is the often asked question, “How do you get the bag down?” When using the ladder setup, we usually have one person slowly lower the bag with the hoist, while another person or two help guide the bag into a bin. If your setup is on wheels, you simply wheel the bag away and lower it right down into your collection container. That’s it, the rest of your brew day will be pretty much the same process as usual.

Hopefully I’ve made it clear how efficient, effective, and low-cost a large-batch BIAB system can be. For a relatively small investment you too can build a large-batch BIAB setup. Prepare yourself for looks of intrigue by neighbors passing by, and looks of envy from other homebrewers. Welcome to Mega BIAB.

Issue: March-April 2018