Why does coffee creamer occasionally curdle as soon as it hits hot coffee, but not always?


Anecdotally this happens to me like 1/100 times I pour creamer into coffee. It can happen with cold half-and-half or the pre-packaged single serve pods that are kept at room temperature.

In: 9


Milk curls when exposed to an acid and coffee is slightly aciding. Normally, coffee is just short of acidic enough to curl milk with a PH of 5 when milk curls at about 4.9-4.75. If the coffee is made slightly thicker or more acidic than normal then it would curl milk.

Don’t worry about this too much. Curled milk is basically unaged cheese and if you keep adding milk it’ll raise the Ph until the milk no longer curls.


Two different things can cause it: the acid content of the coffee and the temperature of the coffee.

If you use a drip coffee maker and are relatively careful measuring your grounds, the results will be consistent enough you see a change in behavior rarely, probably when you do something like change when you pour the coffee.

I use a French Press and I’m kind of lazy, so the amount of grounds I use and how long they steep changes a bit. I see my milk curdle a lot more often than 1/100.