Brewing With Lactose: The Ultimate Guide

by Dane Wilson | Last Updated: April 7, 2023

Hey there! This site is reader-supported and we earn commissions if you purchase products from retailers after clicking on a link from our site.

Did you ever wonder if there was a way to sweeten beer without overfeeding the yeast or making the beer too sugary? Well, there is. For centuries, beer brewers have been at the top of the list when it comes to innovating new ways to make beer look and taste good for various customers. These days, you can find juicy, hazy beers. Lip-puckering, bitter-as-heck beers. You can even grab a beer that tastes smooth, creamy, and even milky. How do the craft brewers do it? It’s called lactose brewing, and it is something you may want to try if you want to develop your own home-brewed milk stout.

Table of Contents

clear drinking glass with stout beer made with lactose brewing

What is Lactose?

Lactose is a type of sugar found in milk and milk-based products. It is a disaccharide, meaning that it is composed of two simple sugar molecules, glucose and galactose, linked together by a beta-glycosidic bond.

Lactose is a unique sugar because it is not as sweet as other common sugars, such as sucrose or fructose. It is also notable because it is not easily fermented by yeast, which means that it does not contribute to the alcohol content of fermented milk-based products such as yogurt or kefir.

Lactose is commonly used as a sweetener and flavoring agent in food products such as candy, baked goods, and ice cream. It is also used in brewing beer, where it contributes sweetness and body to stouts and other dark beers.

Check this video on lactose for beer brewing (as well as a couple of milk stout recipes):

The History of Lactose Brewing

Hearing that some brewers incorporate lactose into their home recipes may sound strange, but the practice is not new. The history of lactose brewing can be traced back to the 19th century, although the exact origins of this technique are a bit murky. There’s one interesting theory that suggests that lactose was first used in brewing as a way to add sweetness and body to beer during a period in human history when sugar was scarce and expensive.

Another fun fact was that, in the 20th century, doctors recommended lactose beer as medicine. Even nursing mothers were drinking the stuff in an attempt to boost their milk production. The British government eventually had to step in and tell people that milk stouts were not medicinal.

One of the earliest examples of lactose beer is believed to be Mackeson Stout, which was first brewed in England in 1907.  Mackeson Stout was known for its rich, creamy texture and sweet, chocolatey flavor, both of which were attributed to the use of lactose in the brewing process.

In the United States, lactose beer gained popularity in the mid-20th century, particularly among home brewers and small-scale craft breweries. One notable example is the Milk Stout brewed by the Left Hand Brewing Company in Colorado, which quickly became a popular choice among beer enthusiasts.

Now, you may be wondering if lactose has been used to sweeten any other form of alcohol. The answer is “not traditionally.” However, some modern craft distilleries have experimented with using lactose to sweeten and add body to certain types of spirits, such as cream liqueurs or milk-based cocktails. These are relatively new innovations, and the use of lactose in this way is not part of any long standing tradition or historical practice in the world of alcohol production.

What Does Lactose Do To Beer?

As mentioned above, lactose is a type of dairy sugar, meaning that it has a bit of natural sweetness to it. That said, it is not as sweet as other forms of sugar, like fructose, or even artificial sweeteners. Aside from adding just a touch of sweet, here are some reasons why a brewer may use lactose brewing:

  1. Body and mouthfeel: Lactose adds body and creaminess to beer, which can help to balance out bitterness and create a smoother, more velvety mouthfeel.
  2. Unique flavor profile: Lactose can provide a distinct and unique flavor profile to beer. If you want to make it stand out from traditional beer styles, give it a try.
  3. Non-fermentable: Because lactose is a non-fermentable sugar, you can add sweetness to your beer without increasing the alcohol content. This is excellent for when you want to make a low alcohol beer.

The Best Times to Add Lactose to Brewing Beer

Wondering when lactose should be added? The specific timing of lactose addition will depend on the desired outcome and the style of beer being brewed. For example, a sweet stout might benefit from lactose added during the boil or fermentation, while a fruit beer might benefit from lactose added during conditioning to balance the acidity of the fruit. 

There are three ideal times when you should incorporate lactose into brewing beer:

During The Boil

The boil is such a significant step, because it pasteurizes the wort, imbues the wort with the flavor of the hops, and can also be a time when adjuncts, like sweeteners, are added. Lactose can be added to the boil along with the other ingredients. This will help to dissolve the lactose and evenly distribute it throughout the beer. However, there is a downside to using lactose at this point: It increases the chance of your beer being too sweet.

During Fermentation

Lactose can also be added during fermentation, once the initial fermentation activity has slowed down. This can help to preserve the sweetness and body of the lactose since it won’t be consumed by the yeast during the primary fermentation. At this point, you can enjoy some added flexibility when adjusting the flavors of the beer.

During Conditioning

Another option is to add lactose during conditioning after the beer has been bottled or kegged. This can help to maintain the sweetness and body of the lactose and can be particularly useful for beers that will be aged for a longer period of time.

The Dos and Don’ts of Lactose Brewing

Let’s take a look at some tips to ensure that your experiment with lactose brewing is a success.


  1. Do use lactose in moderation. Using too much may overpower the beer.
  2. Add in lactose for body. Lactose will add a unique flavor to your beer, as well as provide a heavenly mouthfeel.
  3. Do adjust the amount of lactose based on what you are making. Different types of beer will require various amounts of lactose.
  4. Experiment! Do try various kinds of lactose, such as liquid and powdered, to see how it affects different kinds of beer.


  1. Don’t assume lactose will work in every beer style. Lactose may not be appropriate for every style of beer and should be used thoughtfully based on the desired flavor and mouthfeel.
  2. Do not forget to adjust the recipe for non-fermentable sugars. Since lactose is non-fermentable, it can impact the fermentability and final gravity of the beer, so adjustments may be necessary.
  3. Don’t rely on lactose to mask off-flavors. Lactose can provide sweetness and body, but it won’t cover up off-flavors or other brewing mistakes.

How Much Lactose in Brewing is Too Much?

When it comes to adding lactose to beer, it’s important to strike a balance between sweetness and drinkability. Lactose is a non-fermentable sugar, meaning that it won’t be consumed by yeast during the fermentation process. This can be both a benefit and a drawback, as lactose can provide sweetness and body to beer without contributing to the alcohol content, but it can also impact the overall character of the beer.

In general, lactose is added to beer in small amounts, usually between 2-8% of the total malt bill. The exact amount of lactose used will depend on the style of beer being brewed, as well as the desired flavor and mouthfeel. For example, some brewers may add more lactose to a milk stout or cream ale to create a richer mouthfeel. Others may use less lactose in a fruit beer or IPA to avoid overpowering the other flavors. Go with your gut (unless you’re intolerant, of course).

Using too much lactose in brewing can lead to a beer that is overly sweet and heavy, with a cloying mouthfeel. This can make the beer less drinkable and may impact the overall balance of flavors. Additionally, using too much lactose can impact the fermentability of the beer. Since lactose is non-fermentable, it can contribute to a higher final gravity. This may not be desirable depending on the style of beer being brewed.

The amount of lactose that is considered “too much” will vary depending on the brewer’s recipe and preferences. It’s generally a good idea to start with a small amount of lactose and adjust as needed based on taste tests and feedback from others. Brewers can also experiment with different types of lactose, such as powdered or liquid, to see how they affect the flavor and mouthfeel of the beer.

Can Someone Who Is Lactose Intolerant Drink Beer Sweetened With Lactose?

The answer is yes, you can drink lactose-brewed beer, the same way you can eat pizza or drink milk. There is a reason for this. The usual side effects you may experience when consuming regular forms of dairy are less likely to affect you when imbibing lactose in beer. The lactose used in beer brewing is typically a highly purified form of lactose. In other words, it contains very little, if any, of the other components of milk that can trigger lactose intolerance symptoms.

As such, those who are lactose intolerant may be able to tolerate a serving of beer made through lactose brewing without any issues. You should keep in mind that beer brewing processes vary, and so the beer you make may have more or less lactose than those you purchase in the store or at the bar.

Also, you should monitor your lactose intake. Switch to beers that use non-lactose sugars, if you feel that you may have had too much lactose.

Are There Alternatives To Using Lactose?

While lactose may be the game-changer you have been looking for, it may not always be the best option. Even when the lactose is highly purified, those individuals with lactose intolerance may still be negatively impacted by it. Plus, some people may not like the flavor. The good news is that you can still create a well-round stout or creamy beer without the use of lactose, because there are plenty of alternatives.

Here are a couple of ideas to help you get the ideal balance of sweetness and mouthfeel:

  • Use yeast that has a low attenuation
  • Mash your malt at a higher temperature
  • Play around with the ratio of fermentable and non-fermentable malts to alter the way your beer tastes
  • Experiment with gravity and alcohol bitterness
  • Add caramel malts instead of lactose

A Smooth Result With Lactose Brewing

Lactose brewing is the process of adding lactose, a non-fermentable sugar derived from milk, to beer during the brewing process. Lactose adds sweetness, body, and a creamy mouthfeel to the beer. That is why it is commonly used in stouts and other dark beers. While lactose intolerance may cause issues for some individuals, highly purified lactose used in brewing is often well-tolerated. Overall, lactose beer brewing offers a unique way to experiment with different beer styles and create a delicious drinking experience.

Have you tried lactose brewing or beer made with lactose? What did you think?

Frequently Asked Questions

What does lactose do in brewing?

Lactose brewing is a brewing technique that involves adding lactose, a type of sugar derived from milk, to beer during the brewing process. Lactose is not fermented by the yeast used in beer brewing, which means that it does not get converted into alcohol like other sugars, such as maltose or glucose. This results in a sweeter, fuller-bodied beer with a creamy mouthfeel.

How much lactose do you use when brewing beer?

As a general guideline, lactose can be added at a rate of around 0.5 to 1 pound (227 to 454 grams) per 5-gallon (18.9-liter) batch of beer. That said, the best way to determine the optimal amount of lactose to use in your beer recipe is through experimentation and careful tasting. Try adding lactose incrementally. Tasting the beer as you go can help you find the perfect balance of flavors and sweetness for your beer.

Does lactose add sweetness to beer?

Yes, lactose does add sweetness to beer. The sweetness imparted by lactose is often described as a “milky” or “creamy.” It can balance out the bitterness of roasted malts in stouts and other dark beers. The sweetness of lactose can also contribute to a fuller body and a smooth, creamy mouthfeel in the beer.

Is lactose fermentable in beer?

Lactose is a non-fermentable sugar, which means that it is not broken down by yeast during the fermentation process. Instead, lactose remains in the beer and contributes a residual sweetness to the finished product.