In the busy and rushed world of today, it's tempting to leave brewed coffee out on the counter to be consumed later in the day. But for how long can you leave it? Can you drink old coffee?
It’s happened to all of us. You pour yourself a cup from the pot of coffee that’s been standing on a hot plate for hours and after one sip of the stale brew, you opt for tea instead. Although old coffee won’t kill you, it’s not pleasant to consume.
Most of us realize that coffee doesn’t stay fresh indefinitely after you’ve brewed it. But exactly can you drink old coffee if in a rush?
The short answer is no… unless it's stored cold brew. For a more comprehensive answer, read on.
How Long Do Hot Brews Stay Fresh?
Unfortunately, the quality of a hot brew starts to deteriorate around 30 minutes after brewing when left outside at room temperature. If you leave it out for longer, the coffee starts to lose some of its aromatic compounds, which results in unwanted off-flavors and a bitter taste.
After about two hours, the brewed coffee will have lost its optimum flavor and aroma. The reason for this is that coffee continues to oxidize, even after brewing is completed. This also applies to iced coffee, since it’s just a hot brew that’s been cooled down.
Technically, if you leave a hot brew at room temperature, it will remain safe for consumption for about a day after brewing. The sooner you consume it, however, the less sour and bitter the coffee will be. However, once you add milk or creamer to the coffee, you should drink it within one to two hours.
Apart from not wanting to leave your hot brew out for too long at room temperature, you definitely don’t want to leave a coffee pot on a hot plate. Doing so will lead to a rapid deterioration in flavor and will leave you with a sour and bitter brew sooner than if you left it at room temperature.
You also don’t want to leave brewed coffee in an insulated French press. Even after you’ve plunged the grounds to the bottom of the press, the coffee will continue to brew, which will lead to over-extraction.
How Does Oxidation Work?
Coffee consists of multiple compounds, such as aromatic compounds, acids, sugars, and oils. These compounds, which are often referred to as soluble, create the flavors we love so much in coffee. During the brewing process, when the coffee grounds come into contact with water, these compounds are extracted from the coffee, which releases the coffee’s aromas and flavors.
The process of oxidation continues when the brewing process is completed. When you let your coffee sit, the pH level of the brew will increase due to a reaction between hydrogen and oxygen, which is what gives the coffee a bitter or stale taste. Reheating is worse since it accelerates the oxidation of several compounds and also causes aromas to evaporate.
Tips To Keep Your Hot Brew Fresh for Longer
Here are a few tips you can follow to keep your brewed coffee fresh for longer:
- Once the coffee is brewed, you should immediately remove it from the heat source. Also, if you’ve made coffee in a French press, decant it into another container to prevent over-extraction.
- If there’s coffee left after you’ve enjoyed a cup or two, pour the remainder of the brew into an airtight thermos. This will keep your coffee warm while also slowing down the process of oxidation.
- If you’re not going to have more coffee in the next few hours, you can pour the rest of the brew into an airtight container and put it in the fridge. Stored this way, the brew will stay fresh for about a week. You can then drink it as iced coffee or reheat it. It won’t taste as good as a fresh cup, however.
- You can also freeze coffee if you’ve made a big batch and won’t be consuming it any time soon. Pour the brew into an airtight container and pop it in the freezer. To defrost, place the container in the fridge.
What About Cold Brews?
Since the process of oxidation accelerates when there’s heat involved, cold brews take longer to go stale than hot brews. If you store undiluted cold brew in an airtight container in the fridge, you can easily keep it for up to two weeks. Once the brew starts to taste sharp or sour, stop consuming it and feed it to your plants instead.
Cutting the concentrate with water will shorten the shelf life of the cold brew to about two to three days if stored in a fridge. As is the case with hot brews, you can also freeze cold brews for up to two months. TL;DR: Old cold brew coffee is ok to drink if stored correctly.