The Ultimate Guide to Brewing Kettles: Everything You Need to Know
Buy a kettle about 1.5 to 2 times your batch size. Here is a size chart by batch, plus what matters in material, ports, drains and electric versus gas.
In this post
The short answer: choose a kettle about 1.5–2 times your batch size so a full boil doesn’t boil over: a 10 gal kettle for 5 gal batches. Stainless steel is the long-term choice. Tri-clamp ports let you add a drain valve, thermowell, electric element and whirlpool return without welding, and a bottom drain empties the kettle completely.
| Batch size | Kettle size |
|---|---|
| 2.5 gal (9.5 L) | 5 gal (19 L) |
| 5 gal (19 L) | 10 gal (38 L) |
| 10 gal (38 L) | 15–20 gal (57–76 L) |
| 15 gal (57 L) | 20–30 gal (76–114 L) |
| 20 gal (76 L) | 30 gal (114 L) |
| 1 BBL (31 gal, 117 L) | 50 gal (189 L) |
How big a kettle, and why
You start the boil with more wort than you end with. A 5 gal batch begins the boil with about 6.5 gal (25 L) or more, because you lose around 1–1.5 gal (4–6 L) an hour to steam, plus a little to hops and trub. Early in the boil, wort also foams up before the hot break forms. The extra space in a kettle 1.5–2 times your batch size covers both.
Where a range is given, the smaller kettle works on electric, where you can turn the element down the moment foam starts to climb. On a burner, go bigger. In a single-vessel system, the kettle also holds all the grain and water during the mash, so the grain basket limits how strong a beer you can brew at full volume.
Electric element or burner?
| Element in the wort | Gas burner | Induction | |
|---|---|---|---|
| Where the heat goes | Straight into the liquid | Through the kettle floor | Into the kettle floor |
| Indoors? | Yes, with a steam condenser or hood | Outdoors, or with proper venting | Yes, with a steam condenser or hood |
| Kettle base | Doesn’t matter | Tri-clad base spreads the heat | Needs a magnetic clad base |
| Mash control | A controller holds the setpoint | By hand | By hand or the hob’s settings |
Stainless is a poor conductor of heat, about 1/25 of copper. When heat comes through the floor from a burner, plain stainless makes hot spots that can scorch wort. A tri-clad base sandwiches a conductive aluminium layer between stainless to spread the heat. Induction needs a magnetic base, and 304 stainless isn’t magnetic enough, so induction-ready kettles use a clad base with a magnetic outer layer.
An electric element skips all of that: it sits inside the wort, so the base doesn’t matter. Look for an ultra-low-watt-density element, which spreads its heat over more surface so it doesn’t scorch. Our 5500W tri-clamp element runs on 240V; there’s also a 1650W element for 120V.
Bottom drain or side valve?
| Side valve with dip tube | Bottom drain on a sloped floor | |
|---|---|---|
| What’s left behind | Wort below the pickup tube | Nothing; the kettle empties completely |
| Trub | Spreads over a flat floor | Collects in one spot at the drain |
| Cleaning | Tip the kettle to empty the last of the rinse water | Rinse straight out through the drain |
| Needs | Nothing special | Room under the kettle for the valve |
Our DrainPro boil kettle has a sloped floor to a welded tri-clamp bottom drain. In a Tri-Clad kettle, the HopBlock filter plate keeps hops out of the pump and chiller.
What else to look for
| Feature | What to look for |
|---|---|
| Material | 304 stainless. Aluminium is cheaper and fine on a burner, but strong caustic cleaners attack it. |
| Ports | Tri-clamp for the drain, thermowell, element and whirlpool return |
| Top port or lid | Room for a steam condenser if you boil indoors |
| Volume markings | So you can check pre- and post-boil volumes without a measuring stick |
To clean, rinse while the kettle is still warm, soak with an alkaline brewery cleaner and scrub with a soft pad. Skip steel wool and bleach, which leave rust spots and pitting on stainless.
Frequently asked questions
What size kettle do I need for 5 gallon batches?
10 gal (38 L). It holds the full pre-boil volume with room for foam.
Do I need a tri-clad base on an electric kettle?
No. The element heats the wort directly. A tri-clad base only matters on a burner or induction.
Can I add an electric element to any kettle?
You need a port for it, ideally a welded tri-clamp fitting. Always cover the element with water or wort before you switch it on: running it dry ruins it. See avoiding a dry-fired element.
Should I boil with the lid on?
Use it to get to the boil faster, then take it off. DMS has to escape with the steam. Indoors, a steam condenser deals with the steam instead.
Do I need to sanitize my kettle?
No. The boil sanitizes it. Just clean it well after each brew.
Related guides
Electric brewing for beginners, steam condensers for indoor brewing, the HopBlock filter for Tri-Clad kettles, and the physics of boiling and cooling.