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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.


Saturday 22nd of July 2023

So glad to have found your info! My daughter got us all hooked on raw milk from an area farm in New England. It comes in glass bottles and I don't drink it fast enough. I had a half gallon in the fridge for about 2.5 weeks and it smelled sour. I thought, why not use it in baking? Then I searched for what to do with soured raw milk. My hunch was right. My question though is, I have had the bottle on the counter for 2 days and have been shaking it daily. The "sour" smell has turned a pleasant fermented aroma like sour dough starter. Should I leave it on the counter and not shake it now? And after the 5 days, refrigerate it again to use in baking? Or just leave it on the counter? Thank you in advance.

Butter For All

Monday 24th of July 2023

Hi Fran,

Good instincts!

So once the milk is clabbered you can refrigerate it. Otherwise it will keep fermenting and eventually turn to a firm sour cheese and whey. Once it's separated it's very hard to bake with. Your milk might not even take the full 5 days, just go with your gut, it seems like a good one ;)


Monday 10th of July 2023

So what if my clabber has formed from the fridge? Does it make a difference? The jar has already been opened also and some milk drank. For some reason our raw milk hasn’t “lasted” as long (taste wise for drinkability) and I have a lot of clabber build up but after reading your post on how to form it-I have questions.

Butter For All

Monday 24th of July 2023

Hi Amanda,

Clean raw milk should last 2 weeks. I would read through this explanation from a raw dairy farmer that I respect and trust completely.

"We have an on farm lab where we test Coliform and aerobic standard plate counts. We also test each cow every 3 days for the slightest raised somatic cell count. If a cow has even a slightly raised somatic cell count(like she is fighting a cold) We do not sell her milk. We culture/test the milk with OSU Labs to find out if she is fighting something. The main things that cows can get are strep and staph based mastitis. These are super common and are all over in our environment (on our hands and in the dirt etc). We are incredibly careful in cleaning the cows udders with Iodine and natural soap to make sure there is no bacteria left on the udder and teats before milking. The milk is filtered as it comes out of the cow. It is put in clean jars then put in ice water bath to chill down to 38 degrees degrees with in 15 minutes after it comes from the cow . It sits in the ice bath for 1 hour until cooled to 38-40 degrees. Then its moved to the member store cooler for pick ups. We do milk longevity checks regularly and our milk does not start to turn sour for at least 10-15 days if kept in a spot in the refrigerator that is between 38-40 degrees. So you have a long shelf life on our raw dairy. If you are having problems with it turning sour earlier then 8-10 days, place a thermometer in your refrigerator and check your temps. Temps need to be 35-38 degrees. If you have had problems with milk from other farms souring in a few days this is due to not having the correct cleanliness protocols in place, the cows are not housed cleanly, milk is not being chilled correctly and several other factors about the cows health can contribute."

Now, check with your farm and see if they are following similar protocols. If not, direct them to Mark McAfee and the Raw Milk Institute

If clabber has formed in the fridge then there is quite a bit of bacteria in the milk, not necessarily a health threat unless it's bad bacteria. One thing you could try is freezing the milk be fore it goes off and save it for baking. But I worry that if you aren't enjoying the smell and taste that there is a bigger issue and I would probably advise you to find a different source.

I really hope this helps, and I wish you the best of luck!


Friday 2nd of June 2023

thanks for sharing, my Dad talked about his grandpa liking Clabber, he would skim off the top and eat or put on cereal.


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!!!

Butter For All

Tuesday 25th of April 2023

Hi Jen,

As long as it still smells pleasant, using it in baking is a great way to not waste! Pancakes, waffles, crepes, muffins, quick bread or sourdough. Pretty much any baked good!


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.