Can You Reheat Latte?

Yes, you can reheat a latte, and the result is a warm coffee drink with a slightly different character than the original. The milk foam will not survive reheating: it collapses as the bubbles break. The espresso base changes flavour as the volatile aromatic compounds continue to oxidise after brewing. What you get is a warm, milky coffee that is comforting and perfectly drinkable, just not a precision barista latte.

Can You Reheat a Latte?

Yes. A latte that has been left at room temperature for less than two hours can be reheated safely. Milk should not be left at room temperature for extended periods because it is a good growth medium for bacteria above 4°C (fridge temperature). If your latte has been sitting out for more than two hours in a warm room, discard it rather than reheat it. A latte stored in a sealed container in the fridge keeps for 24 hours and reheats well.

What Happens to the Foam

Milk foam is air suspended in a protein matrix. The proteins in steamed milk denature partially during the original steaming, which is what gives the foam stability. When reheated, especially in a microwave, the liquid expands, the air escapes, and the foam collapses. There is no method of reheating that preserves the foam. If the foam matters to you, froth fresh milk and add it on top after reheating the liquid base.

Reheating a Latte in the Microwave

The fastest method and suitable for most purposes.

1. Transfer to a microwave-safe mug.
2. Microwave at 70% power for 45 seconds.
3. Stir and check the temperature. It should be warm throughout but not scalding: overheated milk develops a slightly cooked, sulphurous flavour from the whey proteins.
4. Add 15-second bursts at 70% if needed.
5. If you want foam, pour the reheated latte into a jar, seal it, shake vigorously for 20 seconds, then microwave the jar lid-off for 15 seconds. This gives a rough approximation of foam.

Reheating a Latte on the Stovetop

Better for preserving the flavour of the espresso base.

1. Pour into a small saucepan over low heat.
2. Heat gently, stirring occasionally, until steam rises and the drink is hot but not boiling.
3. Do not boil: boiling milk causes the proteins to denature further and develops an unpleasant cooked milk taste.
4. Pour into a warmed mug and serve.

Which Method Should You Use?

Q: I love going to little coffee shops to get a latte during my lunch break. I don’t drink all of it, but sadly around the 4 o’clock slump in my office, it is cold and gross. Is there a way I can reheat my latte, so it is just as good?

A: Reheating milk based beverages is not recommended because of separation, curdling, and becoming very sour. However, if you were to make your own latte at home, there are several ways you can do it!

The Stovetop Method

For the most part, using the stovetop will just require a bit of stirring. First, you will want to add the amount of coffee desired, be sure not to add too much, as you should not reheat the leftovers. After you have the coffee in the pot, begin to warm it over medium-low heat. After several minutes, and your coffee is just beginning to warm, add the amount of milk (and sugar) you would like at this point.

It is very important you do not let the mixture boil! Not only will it become bitter, it may boil over causing a mess of curdled milk!

The Microwave Method

The microwave is not recommended to warm coffee as it may become quite bitter. However, if you are already adding sugar and creamer, then it may not be an issue for you. To make a microwave latte, simply add your coffee to a microwave-safe mug, and microwave in 30-second increments until warm. After it is at the desired temperature, add your milk and sugar and stir well.

While you may not get the frothy drink that your coffee shop provides, being able to make and reheat your own latte at home is just as important. So sadly, no you should not reheat your latte because nothing is worse than getting sick, and still having to be in the office for a few more hours.