Small Batch Mash Tun: How To, Pros and Cons, Tips and Tricks

When we started brewing some years ago we did what so many before us (maybe all) have done. We got a kit, scrambled to find everything else we needed, and started prematurely with no clue what we were doing. Naturally, the results were mixed, but we were hooked.

In those early days, one part of the process we found tedious and frustrating was mashing and sparging. Trying to keep the temperatures steady, with small movements of the stove knob, then tossing the grains into a strainer and attempting to ‘slowly’ pour hot water over it. Woof! It really was a pain, even for a 1-gallon batch.

But, like most men or women who want to brew great beer at home, we started researching. The information online can be awfully subjective and tedious, but we came across a mash tun and knew we needed one. Problem was, we didn’t have the capacity or need for a ten gallon mash tun. So, back to the research.

Turns out, it is quite difficult to find a one-to-two gallon mash tun, and buying one already made was a bit pricey. That’s when we decided to make our own, still leery of whether it would actually improve our mash/sparge or not.

Parts and Pieces

We bought ourselves a small cooler, a valve, a bazooka screen, and a stainless steel coupling. A few extra washers might also help to seal it better. We are not affiliated with Amazon, and please use your homebrew supply store if you are fortunate enough to have one, but these are the parts we used. Or, you can find all this stuff at the local hardware store, just make sure it is food grade. It all went together very simply with some minor adjustments to fit our specifications. You will also want a silicon hose to run your wort through after the mash.

We chose this cooler because it was decently small, and the existing valve in it was removable, but it’s worth mentioning that it does say “do not use for hot liquids.” You’ve been warned.

So, how did it work for us?

Pros:

In truth, I can’t believe it took us so long to make one.

The first benefit was that we didn’t have to focus so much on meeting the right temperature--turning the stove up and down, up and down--instead we put in 165℉ water, which cooled to about 150℉ once mixed with the mash, then we covered it and let it do its thing while we prepped for the next steps.

The second benefit is that the clarity of our beer has improved. This is because the grains act as their own filter when they huddle close to the bazooka screen. The difference was immediately noticeable in the wort and the final product. 

The sparge was always a little difficult to get spread evenly over the grains with just a strainer sitting over a brew pot. But with the mash tun, it was easy to slowly rain the sparge water over the grains, creating a smooth flow and even distribution of water compared to dumping it over the grains and getting a hot shot of water through small portions of grains.

This process is also pretty quick. It takes about fifteen minutes for a 1-gallon sparge which limits further enzymatic breakdown, especially when mixed with the sparge water (approx 170-180℉). Obviously, it will be much longer with larger batches, but patience, and water temp, is key.

And, not everyone has this issue, but the mash tun helps keep the heat down in our house. Brewing is a hot process, and that can add a little stress on the A/C bill in our south Texas home.

This is also a process that can be done quite easily by just one person, which is worth noting.

But are there any downfalls?

Cons:

We once brewed a very light table beer. It only had about a pound of grain in the recipe, and when we went to sparge, part of the bazooka screen was above the level of the grains. Needless to say, it made even filtration difficult. So for lower alcohol beers, it may be better to have a false bottom compared to the bazooka screen.

It is also worth mentioning that it can be difficult to clean. Our advice: Just like with all beer equipment, clean it ASAP after use. If not, it will get sticky and the grains will get stuck in the screen, making next brew day a real treat.

I must also say that space is always something that is a challenge in our home, and our mash tun, while economical, could be a little large for some spaces. Brewers with finicky roommates or spouses beware.

Final Thoughts:

Overall, we have enjoyed using our small batch mash tun. It holds temp quite well. It can be shoved into a corner to create space while prepping and cleaning on brew day. It helps to clarify the wort, and it opens up space and time for other things.

It cost us about sixty bucks to make, and we believe it has improved the quality of our beer. And any homebrewer who strives for excellence knows that every bit of effort that improves the final quality is worth it. Consider buying or making your own mash tun.

Brew on!

Mr. Brew

Continue Reading for Mash Tun Tips and Tricks

Mash Tun Tips and Tricks 

Cover the top with a blanket or towel: Our lid is hollow plastic, which is not great for insulation. We cover it to keep the temp inside consistent.

Open the valve slowly, and not all the way: It will actually suck the grain tight to the screen if opened all the way which will cause a compaction and less, or no flow of wort.

Use a silicone hose for transfer to brew pot: It’s easy to clean (you can boil it) and easy to manipulate. It’s just better than the alternatives.

Leave the valve open when finished and cleaned: This will help it dry. Make sure all the water is out of it by working the valve back and forth, then leave it open. Mr. Brew neglected to do this one time and was splashed with a nice dose of fermented wort the next brew day.

Sparge evenly: Use a spoon or a strainer to evenly rain down sparge water over the grains. This will help prevent a tunnel from forming through the grains and will help with even filtration.

Set the used grains in a strainer afterward: You might need to collect the wort that the filter was too high to get out. Or modify your water input to make up for it.

Don’t be afraid to modify: The brewing process is always very similar, but the brewer’s are often not. Set your mash tun to your own specifications, and don’t be afraid to modify as you go.