So I’ve had my L1 for a couple of months now and after initially fitting new piston seals I had fabulous tasting coffee with relative ease. I’m using the following;

Bean: Finca Argentina Estate washed bourbon
Roast date: 2nd October
Basket: 15g VST
water: Volvic
grinder: Mythos 1
tamper: Torr

Ok so I’m dosing at 15g in and pulling the cup @ 24g which I’m getting in 25-30 secs. My problem is, all the lovely sweet nutty flavour has disappeared and it’s very slightly bitter. I’ve been making the grind finer in a bid to ‘fix it’ but the pour is very patchy which suggests to me the grind is too fine. When I loosen off to the point where I get a nice even controlled-looking pour it very quickly gets to a weight of 30+ g in the cup in way less than 20 secs. Suggestions please.

Is it a light, medium or dark roast, think toffee, milk chocolate to plain chocolate as a guide.

  • The coffee is quite old now, so unless it was frozen, it’s going to be hard to get a consistent pour and you are likely to go from choking to a fast pour when you adjust grind.
  • If it was not bitter before, but has developed bitterness, this isn’t a result of coffee aging, but usually brew water temperature (too high), sometimes an excessively fine grind and long pour.

Some suggestions to try and help, although the age of the coffee (unless it’s been frozen, isn’t helping):

  • Try reducing the boiler temperature/pressure, this should help lower brew temperature. e.g. if your boiler pressure is 1.3 bar, try 1.1 bar. With a large boiler, and that type of group/ single boiler system it’s a good idea to get it as low as you can without compromising steaming. Big commercial lever machines often run at 0.9 bar, but you should see if you can get to 1.1 bar. Especially as in the domestic environment you won’t be continuously making shots
  • Avoid the excessively long pours and fine grind
  • see if it does it with more recently roasted coffee, especially as you will be able to grind less fine and get a good pour in the right ballpark time sub 30s.

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