NelisB wrote:I am using a ACS Vesuvius Evo Leva. The Lambro hits the coffee with 100⁰C/212F. With that temperature you will dissolve nasty substances from light roasts. With a longer roast those substances have undergone a (chemical) process that changed the taste. Anyways, this is how I see it.

Can' t you run the Lambro at a lower boiler pressure?
I run mine at 1.3 bar.Never measured temperaure but I estimate the water hits the puck with 96 degrees.
There' s plenty room for lowering the prussure.I ranmy Pompei at 1.3 bar too.Did measurements at the puck and the puck was 96 C at the beginning of the pull.

I had boiler pressure from the Lambro at 1.1 bar. You can tell from the bubbles coming from the group the water is 100⁰C. You wont be able to lower it under 90 in the coffee. Same for Londinium.

All a matter of personal taste I guess.
You sold the Lambro?

espressotime wrote:You sold the Lambro?

No, never

There was a study I found one year ago (I did not save it and can't find it maybe someone can, please) where it showed that in coffee the most acids extracted in the ±94C spot. I think it was 94 to 96C, of course if the beans have acids in them. I found myself many times that increasing the temp with light roasts increases the acidity not sourness but fruity acidity.

In our cases our machines are delivering most of the time a 92-94C brew water at the exit of the group but the puck has a room temp and it's temp will not be 92-94C but less. Hitting the puck with 100C or steam will extract those acids with a much higher intensity in the cup.

When I want to get more acidity out of my brews (cause now i'm only doing drip) I use a higher temp. When I want a more lingering finish with sometimes fruit paste/smoothie I decrease the temp. Body perceived while brewing is higher at 92C than at 100C. The 100C has sharp notes, with a lot of acidity and florals notes.

The OP has a Londinium L1 Legacy model 2016 .This is the brew temperature decline from a Scace Device demonstrated by Andy Schechter (200.6 ° F to 190°).

This is all very interesting to me.

I found myself many times that increasing the temp with light roasts increases the acidity not sourness but fruity acidity.

Perhaps there is an important distinction that has to do with what kind of acidity we want to extract.
The early learning rule-of-thumb is that if the coffee is sour, extract more - hotter temperature, more water, longer contact time, etc.
Often this will indeed take the sourness away. But in my experience it may also increase the sharpness and intensity, which may not always be pleasant. It gets very complicated quickly!

I know Decent guys who extract light roasts on max 85 to 76 C, max 5 bar, SSP HU. I had some extractions from the guy who bought my EK43. He extracts filter roasts only. They were delicious. No sourness. No edginess. Lots of fruit. Juicy. Very different from classic roasts. But true espresso, if you ask me.

baldheadracing wrote:I would try skipping everything under 2., especially no Fellini, lower the dose by a gram or 1.5g, don't use the sintered screen unless you can pre-heat it to the extent that you almost can't touch it, and grind finer to go for 30 second PI.

mrgnomer wrote: If I didn't have the pump my objective would be to fill the grouphead as much as possible, say hold for 20sec or more, gently and slowly let the lever up until the point extraction begins, pull it down again and hold until fill volume and preinfusion catches up to the drips of extraction then let the lever go so the fully compressed spring(s) can do their thing. All that time risks over extraction so I might pull at a start temp of more 80C to 90C.

These were the secret to success. Smaller dose to match a reduced shot volume, ground finer until portafilter was evenly beaded and filled in at about 30 sec of boiler pressure pre infusion. I stopped worrying about a thermosyphon stall, pulled at the top of the 1.3bar PSTAT cycle. Shot was better at the higher temp range, and a 1:2.9 ratio. Sweet like a lemon bar.

And thanks to the link to the old Londinium temp testing videos. I haven't reviewed those since I was considering the purchase. Am enjoying Onyx Monarch now, and looking forward to a light Ethiopian from a roaster new to me, Brandywine. My local shop is now also offering La Cabra....

Mat-O-Matic wrote:These were the secret to success. Smaller dose to match a reduced shot volume, ground finer until portafilter was evenly beaded and filled in at about 30 sec of boiler pressure pre infusion. I stopped worrying about a thermosyphon stall, pulled at the top of the 1.3bar PSTAT cycle. Shot was better at the higher temp range, and a 1:2.9 ratio. Sweet like a lemon bar.

Thank you for the follow up. I tried what @mrgnomer said.

Having the same machine is the OP, with my light roast I used 17.25g in a 16g VST basket that yielded 41.5g out. That tasted a lot better than a 30g out shot. I'm amazed.