trey_antipasto there are probably a lot of people who would want to see how lower pressure maybe favorably brews a specific bean they have picked up. Maybe brew the bean for a week with 1 spring and a week with 2 springs and compare. It hurts nobody to experiment. It simply adds another dynamic to this interesting machine to play with.
Well. Its your machine, it’s up to you how you want to play with it. As @dfk41, it doesn’t make any sense.
I really doubt you are going to find any beans that can benefit from a single spring and not double. Folks here on this thread drink all sorts of coffee from very light to very dark. The Evo gets the best out of the beans.
A single spring experiment won’t go well and we doubt if you will like the cup compared to the shot from double.
It’s not easy to put it back as double as you need to measure the thread screw length exactly where everything sits and you need to compress the springs the same as they were from the factory. It’s not worth the faff and the risks of the springs not going back as they were originally.
Except one or two users like Denis, no one here so far wanted to try the Evo as a single spring lever, let alone make a conversion. Bottom line, if some body wants a single spring, they should get something else.
Our recommendation is don’t do it! Then it is up to you! :-)
Denis, one of the early owners of this machine, tried with a single spring. He was so disappointed with the shots, he had quickly put it back.
You can read Eiffel’s FAQ. This manual is currently being updated. But a version is available as pinned on this forum. Please search the forum from Home. A quick summary of that single spring summary is given here.
Here is what Denis wrote on his experience: I removed one spring, cause in fact that’s why I wanted to take the group apart. You will need a beefy 27mm wrench to unlock the nut holding the two springs. There is some force needed to unlock it. I then removed one spring, cleaned everything and greased with silicone grease food safe and put everything together.. The peak pressure with one spring is at 6.5-6.6 bar and a lot of shot time will be spent at 6 bar, with a slow drop at 4 bar and then the massive drop happens. I only pulled 2-3 shots but the disappointment on my face was too big to continue. I did increase the temp and tried some stuff and will probably give it another go today or tomorrow, but by the looks of it one
spring and low pressure sucks. The shots even if the temperature was adjusted by 2C upwards, after trying at the same temp, gave me some sour bombs that are way to acidic and taste like unripe fruit or if you want, 1 kg of sour lemon juice added over a fruit salad. Denis gave up on the single spring configuration.
