Anybody that drinks espresso is likely familiar with the term ‘dead espresso’. The idea is that espresso should be drunk almost immediately after brewing, after which it rapidly starts to deteriorate up until a point where it is undrinkable and deemed dead. Is this true or false?
Indeed, purists from the Italian tradition will argue that espresso is optimum and should be consumed about ten seconds after brewing. This time frame is a little ridiculous and unrealistic, often resulting in panic, coffee spillage, and burnt mouths.
So let’s look at a more realistic time frame: 1-3 minutes. This is the time it takes for the crema to disappear from the top of a (generally) well-made espresso. Crema is the layer of foam that typically sits on top of an espresso that has just been pulled. It is created when water and oils from the coffee mix and come together with CO2. The common rule in coffee making is that once the crema disappears from an espresso, the shot is dead. Where does this rule come from and is there any truth in it?
Crema contains no real taste in itself. The reason ‘dead’ espresso shots are linked to crema is that this layer of foam actually serves as a brief protective barrier against oxidation.
Oxford languages describe oxidation as the chemical reaction of any substance with oxygen. Oxidation is why we wrap all of our fresh food in saran wrap or keep them airtight in some way. If we don’t the food starts to go stale quicker
The same is true for coffee. When the coffee comes into contact with air it starts to decay. Unfortunately, the speed at which this happens is hugely accelerated when we heat and grind coffee. This is why two very important ingredients for a successful cup of coffee are recently roasted and freshly ground beans.
It is generally recommended, therefore, that we consume a brewed cup of coffee within 30 minutes of brewing. The reason is that, after this time, coffee is said to be stale. But hang on: why does a normal cup of coffee or an Americano stay fresh for 30 minutes when an espresso loses its freshness after 3 minutes? Something feels off here.
Time and Temperature
The real reason behind this double standard is that coffee drinkers are too focused on the crema rule, while the real reason they feel the espresso stops becoming palatable is that it goes cold. An espresso is a small drink with a small amount of mass. Therefore it goes cold very quickly. A big cup of coffee that has a lot more hot water will take a lot longer to go cold, say 30 minutes when exposed to the air.
If we are supposed to drink espresso before the crema disappears because the crema protects the coffee from the air and oxidation, then logically espresso will only start to “go stale” or rather to oxidize, at the 3-minute mark, not before it.
Culturally, when we brew hot coffee it is not a nice experience drinking it after it has gone cold. This is because we are expecting something different to what we taste. However, cold doesn’t mean stale and the two coffee states have been confused with one another in recent times. Indeed, coffee tasters will often allow coffee to cool as they are tasting it. This is because different properties of the coffee are released at different stages after the coffee has been brewed.
In fact, another time frame that is discussed with regard to coffee deterioration is fours hours, at which point the oils in the coffee start to go bad. This is arguably only the start of the “stale journey” so there is theoretically still some flavor to be had from a coffee, even at that stage in its life.
Another point to mention is that reheating coffee further denatures its chemical structure, to a much greater and more rapid degree than it being naturally cooled by the air. This off, harsh and bitter taste from old coffee is often the result of people reheating their cup, in my experience.
The Coffee Journey
I say all of this, of course, to prove a point. A cold coffee that is more than four hours old is not very pleasant to drink, for most people.
However, it does get us thinking: is there really such a thing as a dead espresso shot? There is certainly such thing as a cold espresso shot, but certain different flavors are still available from a brewed espresso long after it would have been deemed dead by the local coffee snob.
Coffee undergoes a journey after brewing, where different notes are brought out of the brew the longer it is in contact with the air. After a certain time, the coffee does become unpleasant and undrinkable, but not dead in the way that coffee society has defined it.
I would recommend experimenting with espresso tasting, with an open mind, as it starts to cool, and see if there are in fact other flavors to be enjoyed from this amazing little beverage. You never know, it might just totally change the coffee game for you!
Featured Image credit: Tyler Nix, Unsplash