Lactose in Beer (How and When to add Lactose)


When you take a look at a nice dark stout, you can’t even tell if its going to be super sweet or not. The only way you would even know is if the brewer told you it was a either a sweet stout or milk stout. The one difference is you guessed it, milk or the more technical term lactose.

If you want to add lactose to beer, put it in during the boil. Lactose does not ferment so it will not create additional alcohol. It will just add sweetness to beer. Lactose in the boil can sometimes throw off hop utilization, but it is negligible and can be accounted for in computer programs.

Lactose is an interesting adjunct when it comes to beer, it has the ability to add sweetness to something that would otherwise be bitter or have a really high alcohol content.

It also adds a lot of complexity and not only can it be added to stouts, but people have begun experimenting and creating milkshake IPA’s among adding it to other styles.

What Lactose Does to Beer

While many beers with lactose in them are called milk stouts, there is technically no milk in them. Instead the lactose or sugary portion of milk is extracted and put into a powder form.

Purchase some lactose for your next brew day today! Its actually not that expensive.

Lactose will make a beer seem less dry. This is because whenever you have residual sugars left in any alcohol it will not have that dry taste. It will also make the beer sweet and thus the reason why some beers are called sweet stouts.

The reason that lactose does not ferment is that yeast lacks the enzyme to ferment it. So the sugars are left sitting in the beer. Its essentially as if you were to back sweeten a beer by adding the ingredient before fermentation.

If you are lactose intolerant adding milk alternatives to your beer will not result in a sweet beer it will just increase abv.

Lactose also adds mouthfeel to a beer on top of the sweetness. It’s likely this mouthfeel is just a result of the residual sugars and not really an actual change, like if you were to add oatmeal to a beer. When you add oatmeal the protein chains are much thicker.

When to Add Lactose to Beer

You can really add lactose to any part of the beer making process. Some of these areas are:

  • During the boil.
  • In Primary Fermentation
  • In Secondary Fermentation.
  • Put in the Keg.

I would hesitate adding it to the mash since it is probably wasteful. But if you really wanted to I’m sure you could, but its likely pointless.

The best time to add lactose to your beer is 15 minutes from the end of the boil. This way your lactose is sterilized and does not interfere with hop utilization.

The Do’s and Don’ts to Adding Lactose in Beer

There are some important factors to take into account when adding lactose to your beer. Some of the things you should do when adding lactose are:

  • Add to increase sweetness of the beer.
  • Add during the boil, or anytime you can be sure it won’t infect your beer.
  • Add near the end of the boil, preferable the last 10-15 minutes.

Below are some things you shouldn’t do when adding lactose to beer.

  • Add too much before tasting it. You could end up with an overly sweet beer if you are not following a recipe you know you will enjoy.
  • Add too early in the boil, as you will offset your hop utilization.
  • If you are lactose intolerant don’t add lactose to your beer.

How Much Lactose To Add?

You can add lactose to a variety of beers it doesn’t just have to be a stout. In fact take a look at some beers that have had lactose added.

  • Nitro White Ale : 4 Hands Brewing Co. First Impression.
  • NEIPA : Evil Twin Brewing IPA Kolata.
  • Berliner Weiss:  Grimm Artisinal Ales Apricot Pop!
  • Milkshake IPA: Narrow Gauge Brewing Co. Big T.
  • Classic Milk Stout: Left Hand Brewing.

Now you would think that each beer would likely have a wide range of lactose quantities added and I’m sure they do, but that range is still the same across styles.

The amount can range from anywhere to half a pound per 5 gallons to 1 pound per 5 gallons. I would suggest that you add a half pound since you can always add more to a keg after taste testing your beer.

You can boil some of the lactose in water to keep it sterile and add it after the boil at anytime.

My recommendation would be to just add half a pound to your first beer and then if its not sweet enough for you add more on your next brew day. No sense in ruining your beer by making it overly sweet.

Spices That Compliment Lactose

If you haven’t checked it out already take a look at my spices in beer article.

It’s really a matter of preference but some spices that compliment lactose in beer are:

  • Nutmeg
  • Cinnamon
  • Vanilla
  • Coffee Beans
  • Chocolate

These flavors are just the begginning as craft breweries are testing out different spices and flavorings in their beer. One of my favorite beers of all time that contains lactose also adds peanut butter to the mix.

You can also add peanut butter to your beer by adding PB2. Learn more about adding nuts to your beer in my other article.

Lactose Intolerance Causes Problems

A large part of the population is actually lactose intolerant. This just means that they can’t drink anything that contains lactose as it will give them gas or other gastrointestinal issues.

I myself perceive myself as not being lactose intolerant and yet I still get gassy when it comes to drinking the peanut butter stout, more so than when drinking other beers.

So if you plan on brewing a beer with lactose in it, make sure you let everyone know what it contains as some people don’t want to be uncomfortable all night, no matter how good it tastes.

Best Yeast to Use with Lactose

Since yeast cannot eat the lactose that you add to the beer it won’t affect the flavor in that way. So really it all comes down to the style of beer that you are brewing.

For example if you are brewing a stout, you will want to use English ale yeasts. The same goes for a NEIPA. But for Berliner Weiss beers you can use German style yeast for a fruity hint addition.

When it comes down to it, you need to pick a yeast with a flavor that compliments the lactose.

Make Beer Sweet Without Lactose

If all you are trying to do is add additional sweetness to your beer, you can do it without adding lactose. The trick is with the yeast and sugar contained in the beer.

Certain yeasts can only survive up to a certain percentage of alcohol. This means all you need to do is formulate your beer with enough excess sugar to push past that ABV hurdle.

The problem with doing this is yeast can survive some pretty high ABV levels so if you want a beer with less in it you will need to find a really weak yeast or take advantage of back sweetening.

Most beer brewers actually don’t back-sweeten their beer but I believe it would work just the same. For example mead makers kill off their yeast and then add more honey to their beer to make it sweeter.

You can kill of yeast by adding potassium sorbate. You won’t be able to bottle condition though and thus will need to keg your beer if you want carbonation.

Learn More about Making Beer

If you liked learning about brewing with lactose make sure you check out the other articles on this site. Since you came here for lactose you might like reading about my oatmeal stout and NEIPA recipe guides.

Bryan

Hey, I'm the the creator of frugalhomebrew.com. I have been brewing beer since 2013 and started by brewing in my parents home. I have written copy on numerous websites. Most notably Seeking Alpha, where I analyze small cap publicly traded companies. I have also written content for netnethunter.com and brokenleginvesting.com.

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