I could really use some advice, friends!

I truly love the type of shots you would typically get from an EK43 - SO's that are bright, fruity, and all-around sweet and delicious.

Do these types of shots always require a machine with a long PI, or a gentle PI with a slow ramp up to full pressure? Some sort of pressure profiling? Or are these do-able on something like the Linea PB with its quick ramp-up to full 9 bar?

I know the PB in particular has the pre-infusion 'pulse', which basically just pulses water at a full 9 bar in intervals, but I presume that doesn't do the same thing?

My question doesn't just extend to the Linea's, of course, but any machine that doesn't offer some sort of build-in PI. Are these sweet SO shots possible on these types of machines, grinding as fine as the shots people tend to go for with the EK? Or do the machines simply choke up?

No you don't need PI or ramp up, but it certainly helps

What these things do is making it easier, give you more option and letting you grind finer, and according to some this makes the shot better and sweeter. For some that is an added plus, But in all honesty I'm not sure I want my shots much sweeter!, but it would be nice with other options!

What I would worry about is the lineas very high free flowrate, the free flow need to get down to 250ml/30sec or close by to get beautiful pulls. The other alternative is to lower brewing pressure but it is really better to mod with smaller restrictors, on a e-61 you'l need 0,5 in the brewhead by user reports, but 0,7mm will do on lower pressure eg. 6,5-8 bar

I can easily pull 35sec shots on a new grinder with scandinavian roasts, the setting is around the two mark so plenty of room to play with and I haven't had a bean through I didn't find tasty, clean and sweet, this with a flat 8bar brew.

That said I plan to upgrade to a Andreja Profiles 1 or Londinium 1

Are you using the turkish burr or the new coffee burr? I've heard new coffee burrs let you grind a bit finer than the old one.
With the old coffee burr it is harder to dial in the shot, usually the run in low 20s with the burrs almost touching. Having pre-infusion helps making it more forgiving shots.
Older Lineas can be retrofitted with 0.6mm gigleur quite easily and adding line pressure preinfusion is not that hard as well.

The EK has the older style coffee burrs as far as I know!

Regarding the older Linea - I believe the newer one does NOT use gicleurs, correct? Is line-pressure pre-infusion still possible on the newer PB's?

Are you able to lower the pump pressure?

That should be an option! I believe TomC has lowered his to around 8 bar for that particular reason, but maybe he'll chime in? I know a few things changed in the PB so it may be completely different, but some sort of PI would be wonderful!

Gicleur is standard on all LM machine now except the Strada EP since it doesn't need one AFAIK.
Linea PB has newer ruby gicleur that's not as prone to clogging as the stainless/brass one on classic Linea. Linea PB also has adjustable pre-wetting which open and close the brew valve during the preinfusion. LM claims this is just as effective as line pressure preinfusion. Pump pressure of course can be adjusted to lower pressure.

Thank you for that info! It seems the Linea's use a .8mm ... Would switching to a .6mm have much effect?

Is there any way to get crazy and add a needle valve or pre-infusion chamber? Or do the electronics get in the way of it working properly? Clearly I'm not a tech so apologies if these questions have obvious answers!

chrisbodnarphoto wrote:Thank you for that info! It seems the Linea's use a .8mm ... Would switching to a .6mm have much effect?

Is there any way to get crazy and add a needle valve or pre-infusion chamber? Or do the electronics get in the way of it working properly? Clearly I'm not a tech so apologies if these questions have obvious answers!

Linea PB's, AFAIK, come with the .6mm Gigleur standard. Their's new absolute on gigleurs - there's 3 options and they're
interchangeable. All the Linea, Linea PB's and GB/5s I've received have the .6mm installed, but I'm not sure if that's
standard USA or standard North America or just standard for my company.

The new gigleur for the PB group cap is super simple to change. Turn off the water, open the bleed valve to
depressurize group (allen #5), take off the two solenoid screws (#4) and then unscrew the gigleur underneath (#2 or #2.5).
I would highly recommend using a .6mm gigleur, I do believe it makes a great difference with channeling - especially with
something that requires precision, like ek shots.

As far as extracting coffees well with/without preinfusion. I would turn off the pump on preinfusion - I personally don't like it.
I feel like if you hit the puck with full pressure and let it sit it will still channel the same then without.
This is an untested theory/opinion, take it with a grain of salt.

I would drop pump to 8 or even 7.5 BAR (adjustable via the bypass screw on the pumphead) and run shots at that
pressure and see what you like.

boost wrote:Gicleur is standard on all LM machine now except the Strada EP since it doesn't need one AFAIK.
Linea PB has newer ruby gicleur that's not as prone to clogging as the stainless/brass one on classic Linea. Linea PB also has adjustable pre-wetting which open and close the brew valve during the preinfusion. LM claims this is just as effective as line pressure preinfusion. Pump pressure of course can be adjusted to lower pressure.

You're right about the EP not having a gigleur. Interestingly enough, LM uses the ruby because they say it's not as prone to scaling, but
some coffee techs I follow in Melbourne actually believe the opposite - rubys clogged more than the brass one.
Regardless, PB group cap is so much better than the solenoid setup on a classic Linea that I'd rather have the easier
to clog/million times easier to swap out gigleur than the classic Linea one.

chrisbodnarphoto wrote:That should be an option! I believe TomC has lowered his to around 8 bar for that particular reason, but maybe he'll chime in? I know a few things changed in the PB so it may be completely different, but some sort of PI would be wonderful!

My Linea is at 6 bar for all my large flat burr brewing (R120).