There are times when I buy and drink Americano in large quantities. The amount is more than I expected, so I can't finish it all at once and end up leaving some. I hate to throw away the leftover coffee, but is it okay to store it and drink it later?

 

Drinking the Americano you had in the morning in the afternoon is okay. An Americano is made only with shots extracted from coffee beans and water, so it deteriorates more slowly than other foods. The process of brewing the beans with hot water sterilizes it, resulting in a low initial contamination level. Additionally, it is difficult for Americano to undergo spoilage, rancidity, or decomposition.

 

Bacteria reproduce and cause proteins to spoil, fats to become rancid, and other components including carbohydrates to deteriorate. An Americano contains little to no proteins, fats, or carbohydrates, making it less likely to spoil. It also exists in an acidic environment (pH 4.8~6), which bacteria dislike.

Mold can grow even in environments where bacteria find it difficult to proliferate. Mold can thrive in environments lacking nutrients and that are acidic, as long as oxygen is present. Even when coffee is brewed with hot water, mold present in the coffee beans does not die and can transfer into the coffee.

Americano has fewer nutrients, so mold growth occurs more slowly compared to other foods, but

 

Mold appears on the surface if left at room temperature for about 5 days. 

Lattes or cappuccinos containing milk are more nutrient-rich than Americanos, so they spoil much faster. It is best not to leave these coffees at room temperature for more than two hours.

 

The risk of Americano spoilage depends on whether the lid was opened and if it was sipped directly.

 

Bacteria inside the cup can transfer to the coffee, increasing the likelihood of spoilage and speeding up the process. When the lid is opened, mold spores floating in the air may settle on the surface of the coffee. It usually takes about five days for mold spores to germinate and grow to a visible size to the human eye. This is why you cannot be assured just because mold is not visible immediately. Coffee that has been touched by the mouth should be finished within 24 hours, no matter how slowly you drink it. If a day has passed, it should be discarded.

 

If it has not been opened and the lid has not been removed, coffee can be kept at room temperature for 5 days. If stored in the refrigerator, it can be kept for up to a week. The Korea Food & Drug Administration considers liquid coffee to be safe when the total bacterial count is 100 CFU/mL or less. According to research by Professor Seong-hee Hwang from the Department of Bio-Food Industry at Semyung University,

 

When coffee purchased from a cafe is stored at room temperature for 5 days, an average of 78.4±29.7 CFU/mL bacteria was detected. When stored in the refrigerator for 5 days, 51.2±32.1 CFU/mL bacteria were detected. Heating the stored coffee once in the microwave kills the bacteria, making it safer to drink.

 

==========================

 

I like coffee, so I end up drinking almost all of it on the same day.

For those who cannot eat it, it is better to discard it within 24 hours.

Is it safe to eat with a straw, or is it better to just discard what's left?

 

It's better for those who eat a little to serve themselves less from the beginning.