Espresso Shot Timing

The 25 to 30 second rule is probably the most repeated piece of espresso advice. It’s a useful starting point, but treating it as a law can lead you away from good coffee. Here’s what shot time actually tells you and how to use it.

When to Start the Clock

There are two common approaches. Some people start timing when they press the button. Others start when the first drops hit the cup.

Starting at the button is more common and easier to repeat, especially on machines with pre-infusion. Whichever you choose, use it every time. Mixing methods makes your notes meaningless.

What Time Tells You

Shot time is mostly a measure of resistance. A finer grind, a higher dose, or a tighter tamp all slow the water down. A coarser grind or a lower dose speeds it up.

Because of that, time is a good diagnostic tool. If yesterday’s shot ran 28 seconds and today’s runs 19 with the same settings, something changed. Maybe the beans aged, maybe the humidity shifted, maybe your espresso tamping was uneven.

Why 25 to 30 Seconds?

The range comes from traditional medium-roast espresso at a 1:2 brew ratio. For that style, 25 to 30 seconds usually lands in the sweet spot of extraction.

But not every coffee is a traditional medium roast. Light roasts often taste better with longer shots, sometimes 35 seconds or more. Some modern recipes run fast, around 15 to 20 seconds, with a coarser grind and high flow. Both can taste excellent.

When to Ignore the Clock

If your shot tastes great at 33 seconds, it’s a great shot. Don’t grind coarser just to hit a number.

The same goes in reverse. A shot that runs exactly 27 seconds can still taste sour or bitter. The time looks right, but something else is off, often the brew ratio, the water temperature, or channeling in the puck.

Taste first, then use time to explain what you tasted.

Using Time to Troubleshoot

Here’s how to read time alongside taste:

Fast and sour. Under-extracted. Grind finer. This is the most common cause of a sour espresso shot.
Slow and bitter. Over-extracted. Grind coarser.
Normal time but sour. Check temperature, ratio, and whether the beans are very light.
Normal time but bitter. Check for dirty equipment, very dark beans, or water that’s too hot.
Normal time but both sour and bitter. Almost always channeling. Work on puck prep.

Pre-Infusion Changes the Math

Machines with pre-infusion soak the puck at low pressure for a few seconds before full pressure kicks in. That adds time without adding much extraction.

If your machine pre-infuses for eight seconds, a 36-second total shot may behave like a 28-second shot on a machine without it. Adjust your expectations rather than chasing the standard window.

Keep It Consistent

To get useful timing data, everything else needs to stay the same. Weigh your dose on a coffee scale, use the same basket, and stop the shot at a set yield.

Consistent shot time is also a sign your equipment is healthy. If times drift without any change on your end, check the shower screen for buildup and consider whether it’s time to descale your espresso machine. Scale can restrict flow and change temperature, both of which show up on the clock.