Brew Kettle Vs Mash Tun (What’s the Difference?)

If you’ve considered moving to all-grain brewing, you may wonder if you need additional equipment like a mash tun to get started. Is it possible to just use your brew kettle without investing in a mash tun?

Brew kettles are usually made of steel, while mash tuns are commonly made of plastic. It is possible to use your aluminum or stainless brew kettle as a mash tun if it has a spigot, thermometer, and false bottom. During the mashing process, a blanket or insulation jacket can be used around the brew kettle to keep the temperature consistent.

Read on to understand the differences between a brew kettle and a mash tun and if you need a mash tun for your next brew.

What is a brew kettle?

It doesn’t matter if you use the extract or all-grain method to brew, all homebrewers require a large vessel for boiling wort. 

In extract and all-grain brewing, a brew kettle is a large stainless steel or aluminum pot used to boil and sterilize the wort. 

Depending on your budget and brewing needs, you have several options when selecting a brew kettle. For small batches, an 8-10 gallon aluminum stockpot or turkey fryer can be used as a brew kettle at a relatively low cost. 

For larger batches, kettles designed specifically for brewing are usually made of stainless steel and have a built-in thermometer and ball valve spigot. Additionally, higher-end kettles have an aluminum bottom that’s encased in stainless steel for better heat conduction and a false bottom for straining grains. 

These more expensive kettles can also double as mash tuns for all-grain brewing. Buying a brew pot that can handle the volume, type, and frequency of brewing you plan to do can make your beer better and help you make the brewing process easier. 

What is a mash tun?

Many all-grain brewers use a separate kettle called a mash tun. Mashing is the process of steeping grains in hot water for an hour or more to activate the malt enzymes that convert the grain starches to fermentable sugars. 

Mash tuns are insulated containers used to maintain a consistent temperature during the mashing process. It also has a false bottom, temperature gauge, and a spigot or valve that helps drain the wort while straining out the grain. Since the mash isn’t boiled, the mash tun can be made out of plastic or metal.

An economical option for a mash tun is to use an insulated beverage cooler fitted with a false bottom for holding the grains and a ball valve spigot. A standard mash tun looks very similar to a beverage cooler but is specifically designed for brewing. 

One thing to note, if your recipe requires a multi-step mash process (lautering) you will not be able to use a plastic mash tun. This process involves heating the mash to higher temperatures over a burner. 

How do homebrewers use a brew kettle and mash tun?

Depending on the style of brew kettle you’re using, the brew kettle and mash tun can be used interchangeably in both extract and all-grain brewing. They are just used at different points in the brewing process.

In extract brewing, the brew kettle is used to boil the wort with hops at the beginning of the brewing process. In all-grain brewing, the mash tun is used to steep grains in hot water at a constant temperature and separate the spent grains from the wort during the sparging/lautering process. 

The brew kettle is also be used to heat strike water for the sparging/lautering process and to transfer it to the hot liquor tank where it’s held until the mashing process finishes. 

Related questions

Can you mash in a brew kettle?

You can mash in a brew kettle, particularly if you use the BIAB (Brew in a Bag) method, but you’ll need to account for these things:

  • Keep the mash at a constant temperature by watching the heat carefully. Alternatively, you can remove the brew kettle from the heat and wrap it with a blanket.
  • The kettle needs to be large enough to accommodate the pre-boil volume and not overflow when the grains are added.
  • You’ll need a false bottom or fine steel strainer to hold the grains in the brew kettle, and a valve or spigot to drain the wort from the spent grains once mashing is complete. 

Can you boil in a mash tun?

If you want to skip the extra step and just boil in your mash tun you need to keep these things in mind:

  • Don’t use a beverage cooler or other plastic vessel as your mash tun because they can’t be heated on a burner.
  • You won’t be able to run concurrent batches because you have to finish your boil and clean your mash tun before you can mash your second batch.
  • You can’t mash and boil in the same mash tun unless you’re using BIAB method because the grains will need to be removed before boiling.