Flow profiling with dark and medium roast coffees - Page 2

Beginner and pro baristas share tips and tricks for making espresso.
Crook6693 (original poster)

#11: Post by Crook6693 (original poster) »

Great response from everyone.

Some have mentioned no Pi just go in flat out to 9bar then back off later in the shot, I'm new and thought you have to do some Pi so not to crack/destroy the grinds in the puck.

My water measurement is based on no portafilter in place, I can with measurements go anywhere from 1g second up to a maximum of 7g second on a BDB, all measured using smart scales.

Just tried a 6s pre which went up to 3bar, slowly started backing off after about 15g in the cup and slowly going back down to 1.6g sec before ending the shot, far better taste.

OK, my thoughts are now to buy some medium beans and medium to dark and explore these, I have always used dark as everyone else seemed to, yes I want to eventually try light but I have no idea if I will like it, can anyone describe light to dark in as far as taste, maybe a silly question :D oh and also trying to buy light freshly roasted beans that you can trust are freshly roasted!! Seems impossible in the UK :cry:

Any advice on medium or medium to dark on how to
I may start to use this style of roast before going to a light or even light to medium.

Oh another question please, R Pavlis water, is it simply to taste better, does it stop Limescale and is it simply the formula below, anyone use RO water and if so what do you add to it, can you use RO instead of distilled water?

10 grams potassium bicarbonate
100 grams distilled water

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baldheadracing
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#12: Post by baldheadracing »

Crook6693 wrote:Some have mentioned no Pi just go in flat out to 9bar then back off later in the shot, I'm new and thought you have to do some Pi so not to crack/destroy the grinds in the puck.
The time between turning the pump on and seeing coffee drip out is pre-infusion. Pre-infusion always happens with espresso (unlike, say, a French Press).

I always turn a pump machine on full for medium-dark or dark roasts, so roughly three to seven seconds of pre-infusion.

A spring lever machine pre-infuses at a lower pressure but at a much higher flow rate than a BDB. The time of pre-infusion remains the same roughly three to seven seconds for dark roasts.

If fracturing/destroying is happening in a BDB, then methods to extend pre-infusion times will not fix the actual issue, which is often puck preparation.
Crook6693 wrote:oh and also trying to buy light freshly roasted beans that you can trust are freshly roasted!! Seems impossible in the UK :cry:
I have only tried a few roasters outside North America, but here's a UK roaster that I've purchased from in the past: https://shop.squaremilecoffee.com/ (Not all their coffee is light-roasted.)
Crook6693 wrote:10 grams potassium bicarbonate
100 grams distilled water
That is a recipe for concentrate. You'd want about 0.01g potassium bicarbonate for 100ml RO or distilled water; doesn't matter which.

The main benefits of RPavlis(RIP) water are that limescale cannot form and the chemistry is, as a gross simplification, beneficial for the copper and brass boilers found in vintage machines with manual refill. Plenty of people use it with other machines, though.

Good luck!

Pressino

#13: Post by Pressino »

Peppersass wrote: Some may disagree, but I firmly believe that flow profiling isn't advisable for darker roasts, and is likely counter-productive.
That may or may not be the case, and if we are talking about an E61 machine with an installed flow control device with the stronger pre-infusion chamber spring, it is very dependent on how the barista adjusts the FCD during extraction.

I have an E61 with FCD that I've used with both the stronger replacement and original stock pre-infusion springs,and I've found that I get more consistently better results from dark roasts using the standard automatic pre-infusion given by the stock spring with the FCD set for "standard" rotary pump water debit and maybe adjusted if needed during extraction to the 8-9 g/s water debit of most vibe pumps.

This is the main reason I think the stock spring is more versatile for an E61 with FCD than the stronger spring, which is mainly designed to eliminate classic automatic E61 preinfusion and allow it all to be done via adjusting the needle valve (read "variable orifice gicleur") of the FCD. Of course with the stock spring you can still have control over flow during extraction, it's just offset from the flow settings used with the stronger spring.

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lancealot

#14: Post by lancealot »

coffeechan wrote:If you wanted to try, a profile copying what a lever does is a good idea.
My previous comment about flow profiling being a waste of time on dark roasts missed this important consideration. I think it a good idea to mimic the trailing profile of a lever with medium to dark roast coffees.