Temperature Profiling (old) L1

Dan Tochterman

am i correct in assuming that a smaller dose, shorter pre-infusion results in higher brew temp?

Reiss Gunson

hi dan

you are correct, the longer you run the pre-infusion the lower the brew temperature drops

reducing the dose doesn't, obviously, change the temperature at which the water makes contact with the coffee but the specific heat capacity of the coffee means that if you use less coffee it will suck less heat out of the water, and perhaps more importantly complete saturation will be achieved faster, which in turn allows a shorter pre-infusion time

you may also want to wind the pressure switch up to 1.4-1.45 bar, assuming you haven't done so already

kind regards

reiss.

Matthew Hoffman

Could one run the pressure switch even higher, say to 2.0 or 2.5 bar, in order to bring the pre-infusion pressure closer to the generally recommended pressure of 3.0 bar.
Matt

Frans Goddijn

The boiler safety valve will likely begin to open at 1.5 bar and prevent higher pressures. Also, the group and the water hitting the puck would get very hot at those higher pressures.

Matthew Hoffman

Thanks, Frans. That's what I needed to know. I figured I could cool the group down with an external fan, as I sometimes do anyway, and then its heatsink properties could temper brew the water temperature during PI. But the magnitudes are probably too great for this fix. In any case, the boiler safety valve limit nixes the whole idea before it can be tested.
Matt

Dan Tochterman

hi reiss,

yes, i had it at 1.4 - 1.45 earlier this year (during the summer) and brought it down because it seemed it was too hot. maybe its because i hadn't broken in the monolith FLAT burrs yet or ambient temp was high (or both), but crema was coming out thin. I lowered it to 1.25 and results have been much better.

i go back and forth between lighter and darker roasts, so i don't know if I want to keep the pstat at its highest setting/temp?

how much would you say is the correlation between temp and pre-infusion time? i.e. the difference between 6 seconds vs 12 seconds of PI? when i first got the machine, i was always dosing 18g (in a 18g vst) with 12 seconds, but having much more consistent results lowering my dose to 17.2g (in the 18g VST) and aprox 11 seconds of PI. probably some of the best espresso i've had at home, ever.

Frans Goddijn

I usually have roasts that are probably on the light side for many and I learned that if I have beans that look dark to me and that tend to taste "too dark", bitter, I need to turn the p-stat a little lower and grind a little coarser. Also dose and tamp in a way that allows a quick pre-infusion, so the first droplets appear after 3-5 seconds and when I release the lever the espresso comes out easily. Not gushing, but also not first dripping and then slowly increasing in flow. Then the espresso that seemed too dark at first, will come out rich creamy and sweet without any unpleasant bitterness.

Matthew Hoffman

Frans Goddijn post=12432 wrote: I usually have roasts that are probably on the light side for many and I learned that if I have beans that look dark to me and that tend to taste "too dark", bitter, I need to turn the p-stat a little lower and grind a little coarser. Also dose and tamp in a way that allows a quick pre-infusion, so the first droplets appear after 3-5 seconds and when I release the lever the espresso comes out easily. Not gushing, but also not first dripping and then slowly increasing in flow. Then the espresso that seemed too dark at first, will come out rich creamy and sweet without any unpleasant bitterness.

Experience tells me that I would have to grind very coarse indeed "for the first droplets to appear after 3-5 seconds" with my L1. Are you perhaps referring to the 3-bar infusion you get with your L1-P?
Matt

Frans Goddijn

Indeed. Such values may also be different between machines and persons because what is 'light' or 'dark' in beans is in part subjective and also a well developed 'light' bean may have a flow like an average 'darker' bean.

But the concept/idea is the same.