How Do You Insulate a Brew Kettle? (And Is It Important)

As a brewer, you are always looking for ways to improve your brewing process. When looking for ways to conserve energy and heat, insulating a brew kettle could be the answer. So how would you insulate a brew kettle and is it necessary?

When working with a limited heat source (including a stove-top oven) or colder environments, adding insulation to a brew kettle may be beneficial. Insulating a brew kettle will help conserve energy and heat, allowing you to increase the volume of wort you can boil effectively at one time, allowing you to brew more beer with the same energy source.

There are different ways and materials you can choose from to insulate your brew kettle. Read on to learn some of the benefits of insulating a brew kettle and how to fabricate your insulation.

Do you need to insulate a brew kettle?

While it is not necessary, it may be beneficial to insulate a brew kettle.

The better a kettle can hold heat, the easier it will be to get to and maintain its temperature, making it much easier if you are using a limited heat source to brew or boil more at one time. It also helps when brewing outside in cooler temperatures.

Insulating a brew kettle will help conserve energy and heat, both important when trying to reach a boil and maintain its temperature after the completed boil. Depending on a few variables like ambient temperature and size of wort, an uninsulated brew kettle will drop 8-10°F per hour, compared to a 1-2°F loss from an insulated one.

Adding the insulation to the outside of the kettle helps keep the heat inside the kettle by preventing less heat from escaping through the kettle walls. 

Insulation will also allow you to boil more wort at one time without having to increase the size of your heating source or its power. A larger wort size will boil more effectively since less heat is escaping than increasing your heat source if the brew kettle is not insulated. 

How to insulate a brew kettle

As the temperatures drop, the time it takes to boil increases, making you brave harsher temperatures outside longer. An insulated brew kettle can be helpful when brewing outside, especially in colder temperatures.

There are several different ways a brewer can insulate their brew kettle. The options range from a DIY creation using a highly reflective material you can find at a hardware store, purchasing a jacket or sleeve online, or even using a sleeping bag and blankets. 

When looking at how to insulate your brew kettle, there are a few things you want to consider. The type of insulation material selected should withstand high temperatures and be flame resistant in case of exposure to open a flame at the time of boiling.

The appearance of an insulated brew kettle could impact the style, design, and material chosen. Also, practicality may be something to consider if wanting to remove the insulation when the brew kettle is not in use. 

Some insulated options available to you as a brewer are: 

  • Reflectix
  • Neoprene
  • Armaflex
  • Blankets/Sleeping bag

Reflectix material

One of the best options for insulating your brew kettle is Reflectix.

Reflectix is a shiny, dense, and non-toxic material that is safe and easy to use. It’s similar to bubble wrap, making it very easy to cut and form around your brew kettle. It can be fastened to your brew kettle using aluminum tape or ties. Velcro is also an option but not recommended since it could melt when heated.

For added insulation, you can create a double layer (with an airspace between each layer). You can find Reflectix in large rolls on your insulation aisle at your local hardware store.

Since it is non-toxic, there is no need for any protective clothing or respirators to install. Although it is not the most alluring-looking material, it is affordable and easy to use. You may remove it when not in use, but that can be more trouble than it is worth. 

Neoprene Jackets

A stylish and durable option for conserving heat is to pick up a neoprene jacket for your brew kettle.

Neoprene is a versatile and tough synthetic rubber. It’s found in wet suits, koozies, and car parts because of its oil, tear, and abrasion-resistant qualities. When manufactured using a closed-cell form, neoprene becomes an excellent insulation material. It is also fire resistant.

Neoprene can be fashioned into a jacket or a sleeve when used to insulate a brew kettle, enabling it to slide off and onto your kettle when it is not needed. A neoprene jacket can come styled or engraved, giving your brew kettle some character which helps if not a fan of the Reflectix look. It works great at keeping the kettle from sweating in warmer weather and can also be used during cold crashing.

Another plus, most jackets are machine washable.


Another option for insulating your brew kettle is to order some ArmaFlex.

Armaflex is the material used to insulate pipes, mechanical insulation, and ductwork. It is a closed-cell foam structure that can come tubular or in sheets. It is ranked in the least flammable category making it heat resistant and withstand an open flame. It is easy to install and can cover pipes, fittings, and handles on your brew kettle. 

You can buy ArmaFlex in bulk, and this can be expensive. It is not removable and may need to be replaced more often due to ArmaFlex becoming hard and brittle over time when exposed over the recommended temperature ratings. The adhesive used to install can be pretty messy as well.

Blankets or Sleeping bags

If you’re looking to not spend much money or you’re in a pinch and need to use something you have on hand, check your closet for an old blanket or sleeping bag to insulate your brewing kettle.

Although you don’t get the energy-saving benefit from an insulated brew kettle using some of the other options, a blanket or sleeping bag is a great option if you don’t want to tinker with your actual brew kettle.

Use the blanket or sleeping bag only after removing the insulated brew kettle from the heat source since the material is not flame resistant. Once removed, wrap the blankets or sleeping bag around the brew kettle and tape.