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Clabber Milk – What It Is, Why You Should Eat It, and How To Make It

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What is clabber milk?

Clabber milk is a naturally fermented milk product that can be eaten raw or used in recipes. It also has a little leavening power all on its own, so it’s great to add to baked goods.

A glass jar of clabber milk with text overlay.

Raw cow’s milk is full of naturally occurring beneficial lactic acid bacteria. When that bacteria is supported with a warm environment, it will ferment the milk and create something like a cross between yogurt and kefir. Eventually, if left to ferment long enough, the clabber milk will separate into curds and whey.

Fermenting or souring milk is VERY different than having milk spoil. Spoiled milk only occurs if the beneficial bacteria found in clean raw cow’s milk have been killed by pasteurization, thus allowing mold spores or other contaminants to flourish.

In a fermented milk product, the lactic acid bacteria have soured the milk with the lactic acids they produce while consuming lactose. The higher acidity keeps other microbes that can be harmful to humans from growing. It is very important that you use only high-quality raw milk from clean grass-fed cows when making clabber milk.

A bowl of clabber milk with honey and crackers.

Clabber milk with honey

Why Should I Eat Clabber Milk?

In Harold McGee’s book “On Food and Cooking, The Science and Lore of the Kitchen” he elaborates on “The Health Benefits of Fermented Milks,” stating:

The standard industrial yogurt and buttermilk bacteria are specialized to grow well in milk and can’t survive inside the human body. But other bacteria found in traditional, spontaneously fermented milk-Lactobacillus fermentum, L. casei, and L. brevis, for example-as well as L. planetarium from pickled vegetables, and the intestinal native L. acidophilus, do take up residence in us. articular strains of these bacteria vPariously adhere to and shield the intestinal wall, secrete antibacterial compounds, boost the body’s immune response to particular disease microbes, dismantle cholesterol and cholesterol-consuming bile acids, and reduce the production of potential carcinogens.

Mr. McGee makes a good case for eating a variety of fermented foods other than commercially produced products.

Making Clabber Milk

The process is very simple.

Start by sterilizing a glass jar and lid in boiling water. To do so, fill your jar with hot tap water to avoid shattering the glass with the heat difference. Add the lid directly to the pan of boiling water, empty the jar of the warm water and pour boiling water into the warmed jar, and let it sit for a few minutes. Empty the jar and air dry the lid and jar on a clean towel. Let the jar and lid cool completely before using.

Add the raw milk to the sterilized jar and secure the lid loosely.

Ferment the raw milk at room temperature until the milk sours and starts to separate. This can take between 1 to 5 days depending on the age of the milk, the temperature in your home, and the natural bacteria in the milk itself.

When the clabber has solidified it can then be skimmed off the clotted cream, used for baking, eaten like yogurt, or strained to separate the curds from the whey.

After straining the clabber, the whey can be used as a starter for any lacto-fermented project from veggies to grains, and is especially useful for starting a new batch of clabber milk. Using a tablespoon of clabber whey in the new batch of milk will speed the fermentation process along considerably. The curds will thicken and sweeten with straining and take on a cream cheese-like texture.


Tuesday 28th of March 2023

Hi! I have a weird question, I left milk, raw and had been through cream separator so it didn't have a ton of cream in it, in the refrigerator for longer than I probably should have to be honest because well life and I kind of forgot. So, anyway it has been about 3 and 1/2 weeks now and it has separated somewhat in its souring. Can I just use this as is? I was thinking about using it for yogurt or in baking? Or can I make something else with it?

Thanks so much!!!


Thursday 16th of February 2023

Hello, I have some raw milk that I put out to make cream cheese because I saw a recipe that said clappering your milk and then straining it can do that. I think it clappered beautifully, however I didn’t realize that at first. I saw the curds and whey separate but I thought there would be a thicker whey layer so I left it out for maybe a week. I opened it today and just directly dumped it into my strainer, cream layer and all. However, first I didn’t realize you needed to secure the lid loosely so when I opened it it made a fizzing sound like I was opening pop. And second, it just smells so sour and a has a bit of a tangy smell in it as well. Did I leave it to clapper too long or is this still ok?

Butter For All

Thursday 16th of February 2023

Hi Josephine,

You can't really clabber too long. The milk will just turn to cheese basically. I can't advise you on whether or not it's safe to consume, but fizzy is a pretty good sign of lactic fermentation. And lactic acid is a great preservative. Take a good whiff and trust your nose on this one! Sour and tangy seems pretty normal. If it smells foul or off, dump it.


Monday 30th of January 2023

Hiya. I left out milk to clabber for about 2 weeks, maybe less. It smelled just fine so I used it for some Irish soda bread. But when I mixed in salt, baking soda, sugar it started to smell a little fishy. Why?

Butter For All

Tuesday 31st of January 2023

Hey Audrey,

It could have been a chemical reaction with the baking soda. The clabber undoubtedly has a lot of acid and when mixed with baking soda it most likely released some gasses. How did it bake up?


Thursday 17th of November 2022

What can happen if you just leave your regular carton of raw milk out on the counter with the lid on? Mine did clabber, but the taste of it ended up kind of bitter. I'm not sure if that's good or not, if clabber is normally supposed to be salted or something after it's done. Can anyone comment on this?

Butter For All

Monday 28th of November 2022

Hi Amy,

If it's pasteurized milk that you left out, it is not safe to consume. If it's raw milk, it should have a sweet and tangy flavor. It may take several batches, using some of the previous clabber, to achieve a nice balance.

It can be salted if you plan to drain the whey and make a quick cheese. Otherwise it's eaten like yogurt, used to soak seeds, or used in baking.

Hope this is helpful!



Sunday 6th of November 2022

I’ve tried to clabber milk twice now. The first time, I got a spot of mold. And this time, I’m on day 5 and it’s still not separating the way it should (it seemed to be working at first but now there’s some thick yellow spots on top and I still don’t have curds and whey). Any tips on what I could be doing wrong?!

Butter For All

Tuesday 8th of November 2022

Hi Lexi!

For the mold, make sure you sanitize your jars, lids and any equipment you use. How fresh is the milk? Because older raw milk clabbers faster than fresh. If the milk is very fresh it can take longer. You can also always help it along by sticking the jar in a warm water bath for a few hours everyday. I hope this helps!