Brewing With Lactose (When To Add, How Much, and FAQ!)

Adding lactose to beer has become a popular trend over the last several years. It adds a rounded sweetness that can be used to balance bitterness in some beers. Brewing with lactose also adds a fuller body and a creamy mouthfeel.

Brewing with lactose at home will take experimentation. Start with a previously brewed beer to use as a baseline for the sweetness. Start with 8oz of lactose for 5 gallons of beer to prevent making the beer too sweet. Add it to the wort 15 minutes before the end of the boil so it won’t interfere with hop utilization. 

Read on to learn more about brewing with lactose. Experiment with adding it to your favorite recipes to expand the flavor profiles of your favorite beers.

Why do brewers use lactose?

Brewers use lactose to add sweetness, body, and a creamy mouthfeel to beer. It can be used to balance out the bitter hops flavors in IPAs. Or to add a subtle sweetness that isn’t cloying like malt-forward beer.

Most recently, the trend of using lactose in brewing is to develop sweet, dessert-like beers. These beers are fruity and creamy tasting like a smoothie or a milkshake. Traditionally lactose has been used in stout beer to add sweetness, body, and its unmistakable silky, creamy texture.

There’s been a trend over the last few years for making beers sweeter. It’s a refreshing change from the previous race to see who could make the driest, most hoppy beers.

How does lactose add sweetness to beer?

Lactose is non-fermentable milk sugar. Brewers’ yeast lacks the enzyme to break down the lactose into alcohol. So it remains in the beer as residual sugar.

How much sweetness does lactose add to beer?

The sweetness varies by the type of beer and how much is used. For stouts, it can take up to a pound to get the full, sweet taste that lactose adds. 

Using 4oz will take the edge off a dry beer. Use over a pound and you risk the beer tasting syrupy. Experimenting with a recipe you’ve brewed before will help you adjust the amount to the sweetness you want to achieve.

History of using lactose in beer

In the late 1800s, it was a common practice to add whole milk to stout beers. They were served during lunchtime to laborers to give them an extra boost of energy to finish their day. Brewers began experimenting with ways to get the same results.

The first commercial milk stout was launched in 1909 by the English brewer Mackeson’s of Hythe. The Brewer wanted to promote more healthful properties it stout beer. They thought that adding milk sure would make the beer seem more nutritious. It was an instant hit and was subsequently licensed to brewers across the country.

Mackeson’s didn’t want their stout to make people fat by adding whole milk. The brewing chemist figured out that by removing the fat, casein, and water from milk that just salts and lactose were left. 

The most common beer styles that include lactose

Adding lactose to beer all started with the milk stout. In the last few years, it has ballooned into a trend to add lactose to many other beer styles. Craft breweries began using lactose in styles where they wanted to boost sweetness or add a creamy texture.

  • New England IPAs: Tired Hands Brewing gets the credit for starting the Milkshake IPA craze. The sweet, fruity flavor of this beer is amplified with the addition of lactose to a New England IPA. It also adds body and a creamy mouthfeel similar to a milkshake.
  • Imperial Cream Ale: The Bruery/Funky Buddha Brewery collaborated on Guava Libre! They use lactose to recreate the sweet, custard-like flavors found in Cuban guava pastries.
  • Berliner Weisse: Cabin Brewing Company makes Staycation Fruited Berliner Weisse with Lactose. It’s very fruity, tart, and quite sweet.
  • Sour/Gose: Grimm Artisan Ales came up with Blueberry Pop! A sour ale made with blueberries, vanilla, and milk sugar. Lactose is used to balance the fruit and smooth the flavor. Instead of a milkshake, this type tastes more like a fruit smoothie.
  • Porter: Cigar City Brewing makes an Imperial Milk Porter with lactose. It has a sweet, silky, full-bodied taste with rich chocolate and hints of dark fruit and toffee.

How is lactose used in brewing beer?

Lactose is used in a variety of ways to enhance the characteristics of the beers it’s used in. 

  • To achieve the specific characteristics like the sweetness and texture of a milk stout.
  • To tone down sour beers and compliment the tartness while adding a body that isn’t normally present.
  • To improve the mouthfeel or flavor of a dry beer.
  • To create new textures and sweet flavors in craft beers for those who aren’t as fond of a traditional beer taste.
  • To experiment with creating more culinary-inspired flavor profiles in craft beer.

How much lactose do you add to beer?

To scale the ingredients of a beer recipe by volume, take each ingredient (all-grain, hops, yeast, spice, fruit, or other flavorings) and divide the volume listed for the recipe, then multiply by the volume you intend to brew.

It is commonly recommended to use lactose at a rate of 5% to 10% of the grain in most recipes. This usually works out to 8oz – 16oz of lactose for a 5-gallon batch. The higher the percentage of lactose, the sweeter the beer will taste. 

It’s also important to consider your mash temperature. Mash temperatures between 152F and 156F are good. Higher mash temperatures leave more unfermentable sugars, which could make your beer sweeter than expected. 

How to use lactose in brewing homebrew beer

Brewing with lactose is pretty easy. Since it doesn’t ferment like other sugars it just stays in the beer adding a subtle sweetness. 

You can add it at nearly any stage starting with the boil. 

During the boil

Most brewers agree that the best time to add lactose to a batch is during the boil. 

Adding lactose for the last 15 minutes of the boil ensures it’s sterilized and won’t dilute your final product. 

Putting lactose in the boil no earlier than 15 minutes before the boil completes also ensures it won’t interfere with hop utilization.

During fermentation

It’s also possible to add lactose to your beer in the second fermentation. 

Calculate and measure the appropriate amount of lactose, then dissolve it in boiling water. Cool the solution before pouring it into the fermenter. 

Don’t just add the powder to the fermenter because it will not dissolve. 

After kegging

Another way of adding lactose is after kegging. 

Measure your lactose and add it to a cup of water. Bring the solution to a boil, then let it cool. Make sure the lactose has cooled before adding it to the keg. 

Gently roll the keg for a minute to ensure the lactose solution mixes into the beer.

When bottling

Lactose can be added just before bottling. It won’t make bottle bombs because lactose is not fermentable so it does not produce CO2. 

You can add lactose into the boiled water with your priming sugar. Carefully stir the mixture into the beer with a sterile spoon. Be careful not to oxidize the beer during this process.

Alternatives to using lactose in homebrewing

There are several alternatives to adding lactose to your homebrew. Below are some ideas to consider that will also add sweetness and body.

  • Mashing malt at higher temperatures leaves more unfermentable sugars.
  • Using yeast types with lower attenuation will leave more sugar and add body.
  • Using crystal malts will increase the sweetness and body of your beer.
  • Backsweeten your beer after fermentation by adding sulfites and potassium sorbate to stop yeast production, then add your desired sweeteners (only for kegs).

Lactose can be a great way to add sweetness, body, and a creamy mouthfeel to many different types of beer. It takes a little experimentation to get the process and amounts where you want them, but the results will be worth it.