How to Brew in a Bag: Beginners Guide

Brewing in a bag is one of the best ways a new homebrewer can get into all-grain. You don’t need a bunch of equipment. It doesn’t take a lot of space and it’s as easy as making a giant batch of tea. If you ever wanted to jump in all grain but never knew where to start. If youre looking to simplify your brewing then stick around.

Brew in a bag is a perfect starting point for new brewers who are looking to make the jump to all-grain. But don’t want to spend a ton of money on a 3 vessel system.

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The Equipment

Brew in a bag method of brewing beer at home.

Brew in a bag is less intimidating for new brewers since the process is one of the simplest of all brewing systems. If you already have a large stockpot you might only need one thing to get started.

Brewing in a bag history is a bit cloudy. No one can quite pinpoint its invention. It really came to popularity thanks to some genius folks in Australia who were looking to simplify their homebrewing process. The main idea about brew in a bag is that instead of 3 vessels that hold the liquid you do it all in one kettle. You use a mesh bag to hold crushed grain and then steep them in hot water to extract the sugars creating the wort.

If you’ve ever made a partial extract kit then you’ve done a smaller form of brew in a bag. In fact, most of the time you are given a small muslin bag to add your specialty grains. The difference is that instead of using extract to make the base of your wort. Youre going to create a much larger bag.

Lets talk about losses

Muslin bag to hold crushed grains in brew in a bag brewing method.

The beauty of brew in a bag is that is all done in one vessel or kettle. That means that at the end of the brew day you only have one pot to clean up. It’s one of the major reasons we stuck with it for so long.

At the very core of brewing in a bag, you only need 2 things to get started. The kettle and the brew bag. The size of the kettle will determine how big of a batch of beer youre looking to make. In general, you need to add a little bit more than your desired final volume to account for the losses. Those losses include:

  • The grain absorption rate is the amount of liquid the crushed grain will soak up when you add them to your kettle. Most brewing software has an estimate for this. Generally, we’re talking about 0.12 quarts per pound of grain. This can vary based on many things but for a 5.5-gallon batch, it can be up to 1 gallon.
  • The boil-off rate is dependent on how vigorous and how long you boil for. The only way to know is to test out a boil with water in your kettle. Set a timer for 30 minutes to see how much is boiled off. Then make notes for future batches.

Brew bags can be made from muslin fabric or nylon. Just make sure that you get one that fits your kettle the best. You might need to do some measuring but there are companies that make them custom fit.

If youre doing a 5 gallon batch of larger youre going to need a way to rapidly heat up all that water. A propane burner is the cheapest way to go. While we’re talking about the heat a good thermometer is useful to hit the right temperature ranges for mashing or steeping the grains. A grain mill is also nice to have. It will allow you to crush the grains to your preference. With brew in a bag, you can go as fine as you want since there’s no concern about a stuck mash like in traditional brewing systems. That means you can get a little more extraction out of grains.

Getting it started

Start by collecting all your ingredients. If you don’t have the kettle space to add the amount of water needed you can always add less water and make a more condensed wort. And then add more water later to hit the right original gravity and volume. So with the water in the kettle, it’s time to heat it up for what’s called the mash. Mashing is when we steep the grains in hot water to convert the starches in the malts to fermentable sugars.

You are basically making a big malt tea and the brew bag is your teabag. The temperature range in which you mash can have many impacts on your beer. The range youre aiming for is anywhere from 145 to 158 F.

The lower you mash the more fermentable sugars you’ll get. Meaning a stronger but lighter body beer. The higher you mash the less fermentable sugars you’ll get. Meaning a sweeter and fuller beer.

Adding the grains

Wooden spoons showing different type and color grains used in beer brewing.

Once you have decided on that temperature you want to mash at you just need to heat the water up slightly above that number. When you add the grains the temperature will drop so give yourself 5 to 10 degrees buffer to help you land on your ideal mash temperature.

First, add in your brew bag then slowly add in your grains. You want to go slow so you don’t get dough balls. That is when the grains clump together and create pockets of malt that are not getting saturated. This will lower your extraction of sugars and you won’t get the most out of your grains.

When the grains are in, set a timer for a mash. Anywhere from 20 to 60 minutes depending on how long you want to wait. Occasionally stirring is a good thing to keep the mash temperature consistent throughout.

Bowls of hops, grains and empty brown bottles all ready for brewing beer.

Finish Up

After the mash times go off you can now pull out the grains. Be careful as it’s hot. Let the bag drain in a bucket or on a cooling rack. You can also squeeze the bag to get more sweet wort out. Others will sparge or rinse the bag with some warm water. If you were not able to start with your required volume of water initially, this is a perfect time to add it in as sparge water.

Once youre satisfied with getting the water out of the bag you can damp those grains in compost. At this point, you officially have your wort. You just did all-grain brew in a bag. It’s really that simple and the wort is in the kettle ready to be boiled and have hops added. Just like you would on an extract kit. The rest of the brew day would go as you normally would.

Different beer glasses filled with different types of beer styles.

The Pros and Cons of Brew in a Bag

The positive side of brew in a bag:

  • Limited equipment needed to start.
  • You don’t need to have a lot of space.
  • Quicker and more simple brew day compared to traditional systems.
  • Easy to clean up.
  • It gets you into all grain faster

The negative side of brew in a bag:

  • The bag can be heavy to pick up.
  • Efficiency can be lower.
  • It can be hard to control mash temperature in the kettle

For the beginner, it’s the easiest and least expensive way to make the jump from the extract. Which in the end will help you have more control over the ingredients and the quality of beer you make. Brewing to us is all about having fun and making something delicious. Cheers.

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