Single- and Two-Vessel Brew Systems

Any brewer aspiring to go all-grain with their brewing hobby needs to figure out where they are going to perform their mashes and how they will separate the grains from the wort. There are many approaches homebrewers can take and it just depends on which one appeals to your interests the most (as well as your budget). In reality, after a few years in the hobby many homebrewers will often have more than one mashing system and will alter between them depending on the recipe and its demands.

Today we’re going to start with the single- and two-vessel systems. Less space requirements mean they are ideal for brewers working in smaller spaces. Due to the complexities and various configurations found in three-vessel systems (though they can be very simple), we’ll leave those for another day.

Single-Vessel Brew Systems

mashing in with a brew-in-a-bag, single-vessel system
Brew-In-A-Bag mashing system is cost-effective and easy to perform.

This style of mashing is by far the simplest means of all-grain brewing. The most basic of these setups requires just a few pieces of equipment: A large stockpot or brew kettle, a quality mesh bag (preferably built for the task and sized for the stockpot or kettle), a pair of brewing gloves, and a heat source. Heat the mash water, place the crushed grains in the bag, submerge the bag and grains into the water, then cover and wrap with something like a sleeping bag to retain heat. When the mash is complete, simply lift the bag out of the wort (wear those gloves!), then bring the wort up to a boil . . . done.

On the negative side, it can yield the lowest efficiency of the various mash configurations in terms of sugars extracted from the grains and may result in higher wort turbidity (cloudiness) that could be an issue with a delicate beer like a Pilsner. On the other side of the coin, there is no sparging required and there is only one pot to clean. Also, there is only one calculation needed for water volume to account for liquid absorption by the grain to hit your target volumes.

A commercially produced single-vessel brew system. Photo courtesy of BSG Handcraft

There are a couple areas of note about this style of system, first of which is that some Brew-In-A-Bag (BIAB)-style systems utilize a metal perforated basket inside the stockpot instead of a mesh bag. While this setup costs more, one big benefit is that the basket can be hung above the wort and can remain there while more wort slowly drains out of the grains. While it’s hanging there, sparging (washing) the grains can occur too. There are a host of manufacturers producing single-vessel all-in-one brew systems so a search around the internet will yield a treasure trove of options serving many budgets. Many of these purpose-built systems also have a built-in electric heat source, temperature control, and recirculation pumps.

If you do utilize a bag and plan to brew more than 3-gallon (11-L) batches, you’ll probably want to figure out a way to hang the bag above the wort. Many homebrewers utilize a tripod, ladder, hold, or hoist, to accomplish this goal. A quick search online will yield a multitude of different solutions homebrewers have come up with. A final note about those who do utilize bags in their BIAB setup: Don’t be afraid to squeeze the bag. The fear of a compound called tannins is a threat with other mash systems, but it has more to do with the pH of the grains from which the tannins leach from. pH is not an issue here, so feel free to twist that bag and squeeze to wring wort out of those grains in order to maximize your efficiency.

Two-Vessel Configurations

The two-vessel configuration typically is a step up in terms of equipment requirements since a second large stockpot (both with bottom valves for draining) is required, and will almost always feature a temperature monitoring system as well as a pump to recirculate the wort between vessels. Brewing efficiency does go up as does the ability to produce cleaner styles of beers, but so does the complexity and cleaning needs of your brew day. Also, larger batch sizes can be accomplished with smaller pots using a two-vessel system. Various brewing equipment providers have their own proprietary systems or DIYers can rig up their own two-vessel system. 

a picture of Blichmann Engineering's breweasy system
An example of a commerically produced two-vessel system. Photo courtesy of Blichmann Engineering

One vessel in this configuration acts as both the hot liquor tank and brew kettle, while the second vessel is the mash tun. Water is heated in the hot liquor (brewers refer to water as “liquor”) tank, then moved into the mash tun along with the grains. The mash tun must be equipped with a means to separate the liquid from the grains. Perforated metal baskets, false bottoms, stainless steel braids, and conduit piping systems are some of the ways homebrewers accomplish this. An online search “how to build a mash tun” will yield many options.

The wort from the mash tun will be slowly drained back into the first vessel, where it is warmed back up via heat source before being pumped back to the mash tun. After initial mixing and settling, the circuit runs during the mash to maintain your set mash temperature and attention needs to be paid that the cycle between the two vessels runs at nearly the same speed. When the mash is complete, the wort is then drained from the mash tun into the first vessel where the boil can proceed and the mash tun can then be emptied and cleaned.

Issue: November 2023