The Best Mash Tuns for Homebrewing

The decision

Insulation or heat: pick one

Every mash tun is solving the same problem -- hold a grain bed at a chosen temperature for an hour -- and there are only two ways to do it. Insulate the vessel so the heat cannot leave, or leave the vessel uninsulated and keep adding heat. Those two approaches lead to completely different purchases, and the rest of this category is detail.

An insulated tun wins the simple case decisively. Mash in at your strike temperature, close the lid, walk away for an hour and come back to a mash that has drifted a degree or two. No element, no pump, no controller, nothing to fail. For a single-infusion mash, which is what the overwhelming majority of homebrew recipes call for, there is nothing an electric system does better.

A heated tun wins when you want to change the temperature during the rest. Step mashing -- a protein rest, then a saccharification rest, then a mash-out -- requires raising the mash several times, and doing that in an insulated cooler means calculating and adding infusions of boiling water, which both works and is tedious. If step mashing is your reason for being here, the honest answer is often an electric all-in-one system rather than a mash tun at all.

The false bottom

The part that actually does the work

Whatever the vessel, the component that makes it a mash tun is the thing separating wort from grain. A domed, perforated stainless false bottom is the best version of it: the dome resists collapsing under the weight of a saturated grain bed, the perforations are fine enough to hold back husk, and the curve means less wort is trapped underneath as dead space than a flat plate leaves.

The one thing people get wrong is sizing. A false bottom has to match the vessel's internal diameter closely. Too small and grain escapes around the edge into your pickup. Too large and it does not seat. This is a measurement, not an estimate, and the full detail is in false bottom explained.

Sizing

Ten gallons for a 5 gallon batch

Mash tun capacity is set by grain volume plus strike water, not by batch volume. A 5 gallon batch of ordinary-gravity beer is around 10 to 11 pounds of grain, and grain occupies roughly 0.08 gallons per pound once saturated. Add the strike water at a typical 1.25 to 1.5 quarts per pound and a 5 gallon batch wants about 6 to 7 gallons of working volume.

Ten gallons is therefore the standard homebrew mash tun size, and it is standard because it also handles a 6 gallon batch, a high-gravity 5 gallon batch with a 15 pound grain bill, and a thicker mash if you want one. Eight gallons works for ordinary beer and runs out on anything ambitious. Fifteen gallons is for 10 gallon batches.

• 5 gallon batches, ordinary gravity: 8 gallons minimum, 10 gallons comfortable.
• 5 gallon batches, big beer: 10 gallons, because a barleywine grain bill is nearly double a pale ale's.
• 10 gallon batches: 15 gallons and up. This is usually the point at which an insulated cooler stops being practical and a kettle tun with a pump makes more sense.

Three mistakes

What goes wrong in practice

• Preheating is skipped. A cold vessel steals several degrees from your strike water on contact. Rinse the tun with hot water for a few minutes before mashing in, dump it, and your strike temperature calculation suddenly works.
• Dead space is not measured. Every tun holds some wort below the pickup that you will never recover. Measure it once by filling with water until liquid just appears at the valve, and then account for it in every recipe. Unmeasured dead space is the most common cause of coming up short in the kettle.
• The bed is compacted. Pulling wort too fast compresses the grain bed against the false bottom and sets a stuck sparge. Open the valve partially, accept a slower runoff, and the problem does not occur.

How we picked

The basis for these

Selected on published manufacturer specifications for capacity, insulation, fittings and false bottom geometry, plus long-standing homebrew practice on grain absorption and mash thickness. The heat retention figures are the manufacturers' and the homebrew community's documented range, not results from our own measured trials. See how we pick.