When Do I start timing the shot, how much volume of coffee should I extract?
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This is a question that comes up from time to time on the forums.
I was trained that a typical shot should fall into the 18-24 second range. I have always started timing at the first drip of espresso from the portafilter. Another opinion has recently surfaced indicating that timing begins when the button is pushed. Which is correct or is there another way?"
Timings
18 is probably at the fast end of the scale and up to 35 seconds can be OK….but it depends on the coffee and it also depends on when it starts blonding (as you should kill the shot then). I don't mean just lightening slightly as there is a tendency (these days) for people to stop shots too early.
It is normally timed from the point the button is pressed, lever is thrown etc. but a vibe pumps have a much lower flow rate and pressure ramp up than the rotary pumps, the pressure ramp-up is faster, so the same shot would be slightly shorter (all other things being equal). You can clearly see this using a pressure measuring portafilter and this is likely to influence things a little.
Timings are a guide not a rule, stop the shot when it blondes (the stream gets light and watery), but don't confuse it with a lighter stream that often results from very fresh coffee. If thats happening under 20sec, grind a bit finer, if its happening over 30 sec, grind a bit coarser. In addition to all this you have to be mindful of coffee dose and shot volume. It's no good having a 24 second shot that's only 15ml! There does seem to be a current trend to pull "short shots" for the volume of coffee used ("ristretto" type shots).
Volumes
This is a slightly more difficult area, WBC rules have a definition of what's "correct" (and I think it's changed over the years), specifying the level of Crema + Liquid be to a certain point. This does not necessarily traslate well to the home environment, simply because a coffee that produces more crema will by definition have less liquid through it, but I believe there is a rider that gives guidelines to the amount of crema vs liquid. However, were not talking about a Barista competition, were talking about something you're drinking at home, if you enter a competition, you need to make the coffee by their rules.
You want to stop when the extraction is finished….e.g. it blondes. For a Single If that happens and the liquid volume is more than 5mm below the line (or above the line) in a 1 oz shot glass, you may want to make some adjustments. This is because the baskets themselves can be over/under dosed. If your pulling a double, simply apply the same criteria for two 1oz lined shot glasses (one under each spout), or proportionally more for a single 2 oz shot-glass.
This Photo shows evidence of the start of blonding in an espresso extraction….note the white spot in the crema (click to enlarge).
The photo below shows a double shot from an Andreja Premium and 2 common faults, the machine is not level (adjust the feet if possible), stopping the shot slightly too late, the volumes of both are too much. Although the right hand shot is almost OK (click to enlarge).
There are a few factors that can affect blonding;
- Roast
- Tamp
- Grind
- Brew Pressure
- Temperature
- Type of Coffee
- Dose (g of coffee used)
Now you may have read that the correct dose of coffee is 7g for a single and 14g for a double. Most people I see pulling shots dose 8-10g for single and 16-20g for a double. So of course the volume of correctly extracted shot is going to be different in each case, depending on the dose used. My personal experience has been that with 7g of coffee in a single basket, it's difficult to get a good shot and a little more helps enormously.
Try NOT let the coffee touch the shower screen (with some machines a screw/nut indentation is unavoidable) and a rule of thumb with dosing:
- A single - dose to about 3mm below the top of the basket, then tamp
- A double - dose level with the top of the basket, then tamp
Below a few common problems of dosing (temp) and grind
The grind may be slightly too fine and you can get a wettish puck (click to enlarge)
The temperature can be too high and you get a cratered puck, especially if the basket is not well loaded…..this basket barely had 7g in it. This makes it very difficult with a single (click to enlarge).
