coffeeespresso
When pulling a shot of espresso, how long is its life before it is too bitter?
I know this might change by the bean, but what is a rough estimate?
I was doing some coffee tasting and some of the shots were left unused for about 5 minutes and the barista said that these shots were now "dead" and that they don't reflect what the true taste of the coffee is.
Do I really only have 5 minutes to drink espresso before its no longer drinkable?
It could simply be that it's a gustatory illusion! See my answer to this related question for more explanation.
Edit:
Here is a summary of the relevant information (if you don't want to follow the links):
Human taste receptors don't simply react to how much actual salt there is in a food or drink; our perceived tastes are a fusion of both our gustatory and olfactory senses. In other words, the smell of a food or drink can affect how it tastes!
There are numerous studies that suggest foods with certain odors can be perceived as much saltier than they actually are. Coffee has a good amount of oil, there's even more fat if you add cream, and other studies suggest that high fat foods can also increase perceived saltiness.
Grinding coffee for espresso is probably the most difficult to get right. The coffee grind needs to be fine enough to increase the pressure required to push the water through the filter and create a good crema. But if the grind is too fine, the ground coffee can block the coffee filter. Generally, espresso coffee grind resembles a mixture of powdered sugar and fine beach sand. Since each espresso machine is a bit different, you may have to experiment to get the coffee grind just right (Allmann Bros Coffee).
Brewing espresso is particularly susceptible to problems relating to an inconsistent grind. I am not familiar with a burr mill specifically, however burr mills are generally recommended for espresso grinds as they tend to provide consistency. Bear in mind that the grind can either be too coarse and the water will run through without much extraction due to the pressure and space between the grinds, or it can be too fine and allow for a backup of water and espresso water and grinds all over your counter.
NOTE: The pressure with which you pack/tamp the puck (the grinds when pressed in the brewing basket form a puck) will also play an important role in the extraction process and the crema formation. You can get a feel for how hard to tamp the puck by getting a scale and pressing down until you hit about 30 pounds of pressure; you want to pack the puck at that pressure of tamp.
Best Answer
This barista says no, you can enjoy your shot for a little while:
I am not an espresso fan myself--I like regular coffee, but not after it has cooled down, and never reheated. Many folks are perfectly content to microwave a cold cup and drink it.
I imagine that older, colder espresso is palatable to you to the extent that you are willing to tolerate it. A small shot of coffee--and lets face it, that is all espresso is, even if it is brewed in a fancy manner--is going to cool off much more rapidly than a full cup, or a full pot.