Why Do Oils in Coffee Matter for Home Espresso Machines?

Buying pre-ground coffee is the most common home espresso mistake. A capable machine with stale grounds still produces poor shots. Freshly roasted whole beans and an espresso grinder matter more, because flavor in coffee dissipates quickly after grinding, and espresso grind is fine enough that the loss speeds up further.

The oils in coffee and the carbon dioxide they trap form crema, so pre-ground coffee gives a thinner layer even on a machine that holds nine bars steadily. Pre-ground bags also run from one pound to a kilogram, more than most households finish before flavor fades. Grind setting is equally critical, which is why coffee shops adjust coffee machines every morning as parameters shift daily.

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As some high-performance coffee machines have become more compact, their household positioning has become increasingly obvious, and many friends have also fallen into the pit of espresso. Therefore, Front Street would like to share some common problems when making espresso at home.

1. Buying pre-ground coffee

But if you want to taste espresso with good flavor, Front Street still recommends equipping yourself with an espresso grinder and buying freshly roasted whole beans. There are three reasons. First, the flavor of coffee dissipates very quickly after grinding, and especially when ground as fine as espresso, the flavor volatilizes even faster. Espresso coffee is sold in specifications ranging from at least 1 pound to as much as 1 kilogram, so it is difficult to finish drinking it before the flavor of the coffee grounds has dissipated. This easily leads to waste.

Some friends also ask: I have a grinder, usually used for grinding pour-over beans. Can it be used to grind for espresso? According to Front Street's understanding, most grinders find it difficult to perfectly accommodate both grind sizes. The burrs for espresso and the burrs for pour-over are different.

Take the EK43s used in Front Street's store as an example. Even if the setting is adjusted to the finest, the coffee grounds produced are still coarser than those from an espresso grinder. So if you have already bought the coffee machine, one more espresso grinder is not a big deal.

2. Repeatedly tamping the puck

Some friends may feel after tamping that there is a bit too little coffee, so they add some more coffee to the portafilter basket and tamp again. This is also very likely to cause "channeling." The correct approach is, if you find the dose is too small, first break up the tamped coffee back into a fluffy state, then add an appropriate amount of coffee grounds, and then tamp.

3. Locking the portafilter onto the group head and then delaying before starting extraction

The above content is compiled by CoffeeHunters, a coffee news website.