I’m thinking of transferring to manual machine from a semi automatic machine. What are the differences between manual and semi-automatic machines? I'm interested in how difficult they are to use and in getting consistent results.
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Go manual and you’ll never go back. It’s like a stick shift: more fun ‘cause there is more to play with! I think there are numerous advantages:
Blessed silence. Pumps are not music to my ears when my brain is not yet caffeinated. I prefer to listen to hummingbirds outside the kitchen window than an espresso pump.
Awareness. You can feel the resistance of water flowing through the coffee. If you change the grind or tamping pressure, you get immediate feedback on how it has affected the extraction process. Grind beans straight from the freezer? It is obvious how temperature affects grind size.
Assessing Grind/Tamping combination. Perfusion is determined by the product of grind size and tamping pressure. If your grind is a bit too course, this can be compensated by slightly harder tamping. How do you tell if you have the right combo? Count how many seconds it takes for the first drop to come out of the portafilter on boiler pressure alone. I use 4 seconds as the magic number. If I switch beans and the time goes up to 7 seconds, I know the new beans need a courser grind or a lighter tamp.
Pre-infusion: Boiler pressure (1 bar) is perfect for pre-infusion. This allows the grounds to soak through to their centers before extraction begins. I count off 10 seconds of pre-infusion before pulling the shot.
Control of extraction time: How hard you lean on the lever will determine how long the extraction time is. I shoot for a total of 25 seconds from beginning of pre-infusion to the end of extraction.
All this becomes a flexible dance. Say you try a new bean but notice first drip time has gone up to 8 seconds. Reach over and tweak the grinder a bit courser. You know extraction time will be longer so shorten pre-infusion to 6 seconds. Use higher than normal pressure on the lever to keep extraction time to under 30 seconds. Extra crema from that higher pressure! Great shot but you know the next will be even better because the grinder has already been adjusted.
As satisfying as a heal-and-toe downshift in a decreasing radius corner.
OK, maybe not that good. But you can do the Emperor’s New Clothes routine on your guests.
