Flow profiling with dark and medium roast coffees

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by Crook6693 »

Hey all new member here.

Breville dual boiler with slayer modification, I enjoy flow profiling but would like advice or where to look for profiling especially with dark and medium to dark roasts please, pre infusion times, grams per second when etc.

Such a huge site of knowledge and know how, we'll yep I've fried my brain trying to find any charts or know how.

Can anyone point me in the right direction or even let me know your know how or tips and tricks, current 9 day old beans dark coming out bitter, tasteless sometimes, 10 second pre at 1.6gs, 20 in 35g out in about 30 seconds.

Thanks all

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#2: Post by Peppersass »

Tasteless espresso is most likely due to stale beans. Darker roasts tend to stale more quickly than lighter roasts, especially if not kept in an airtight container.

Some may disagree, but I firmly believe that flow profiling isn't advisable for darker roasts, and is likely counter-productive.

Flow profiling was developed in order to extract more from light and light-medium roasts, which can be notoriously difficult to pull as espresso. If you pull them with traditional espresso parameters (e.g., 1:2 brew ratio in 25-35 seconds), they're often sour, indicating under-extraction.

The idea behind flow profiling is that it allows you to grind super-fine without choking your machine. The finer grind exposes more surface area for extraction, while the long, slow pre-infusion loosens the puck and provides more contact time for the water. The combination can help to fully extract a light roast.

Dark roasts extract quite easily, so if you grind fine and use long, slow preinfusion, you're likely to over-extract and get bitter, roasty, acrid and/or ashen flavors. It's best to grind dark roasts coarser so they extract in 25-30 seconds or so with the machine's normal preinfusion (usually just a few seconds to ramp to full pressure.) Lower temperature can help as well.

Another technique for coping with over-extraction of dark roasts is to grind coarser, updose and pull Ristretto. For example, 20g dose producing 20g-30g of beverage in 25 seconds. Again, don't use long, slow preinfusion.
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#3: Post by Ken5 »

Crook6693 wrote: 10 second pre at 1.6gs
20 in 35g out in about 30 seconds.
10 second preinfusion at 1.6 g/s? 16 grams before you even pull?

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#4: Post by Jeff »

My very rough estimates are that my 17 g of grinds takes around 20 g of water to saturate, so those numbers seem reasonable to me.

I'm not sure that darker roasts benefit from extended soak times. My experience has been that darker roasts can be challenging to balance the roast bitterness with other flavor components. Often this means shorter ratios, cutting a shot short of blonding, and/or lower temperatures. A soak, once saturated, tends to increase extraction. While this is often a benefit for light roasts, which tend to be harder to extract, for darker roasts I found it emphasized the bitterness.

Where I'd consider using flow profiling with a darker roast is during the high-pressure extraction. A declining-pressure profile can sometimes result in a better balance of flavor components, in my experience.

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#5: Post by Ken5 »

So the g/s is clean hot water measured coming out of the brew head rather than espresso coming out of the basket?

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#6: Post by Nunas »

10 second pre at 1.6gs 20 in 35g out in about 30 seconds.
I'm not clear on what you mean by preinfusion. Usually on preinfusion nothing comes out; I don't see how you could be measuring flow. So, do you mean 10 seconds preinfusion at 1.6 bar? For the 20 in 35g out in 30 seconds, I presume you mean a dose of 20g and a yield of 35g, pulled over 30 seconds. The time is about right, and the shot should be a strong normale (i.e., a bit less than 1:2).


#7: Post by walr00s »

I'm not clear on what you mean by preinfusion. Usually on preinfusion nothing comes out;
Pretty sure 1.6gs refers to the water debit. So not necessarily any yield and unlikely to be anywhere near 16g.

I'd agree that you should try different beans and also possibly adjust your water recipe. When I run zerowater through my machine (with no potassium bicarb), I often get watery espresso with muted flavors. Also agree that for darker roasts, you do not want to grind fine enough to need such a long preinfusion, as the result is likely to be extremely bitter.

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#8: Post by lancealot »

Peppersass wrote: Some may disagree, but I firmly believe that flow profiling isn't advisable for darker roasts, and is likely counter-productive.
Agreed. In my experience, I can coax out different flavors by flow profiling medium dark - dark roasts, but I never get anything better. I now regard it as a waste of time for that kind of coffee.

There are a few dark roasts that I like, Counter Culture 46, Blue Bottle Hayes Valley... They tend to get over extracted when pulled to contemporary standards, so I pack the basket and pull them short: Stuff the basket and pull it short!


#9: Post by cmin replying to lancealot »

Try Chromatics Opus, god I love that stuff, one of the only dark roast I love, they messaged me back one day when I told them how impressed. I was with it and they said they laser analyze durring/post roast. Manages to be dark, with no oil, and no bad bitterness etc.

I've been not using PI or profiling initially on thr BDB for some beans (as you know haha). Have a medium Brazil tomorrow so we'll see. But that Atomic Blend I was using from Anodyne I was just letting pull like normal full open than slightly pulling back on flow. I could not shake that off putting bitterness with long PI, oddly just letting rip and still pulling say 19g/35g out but at 45 seconds was waaaay better than trying to profile or PI into that range or just over 50 sec


#10: Post by coffeechan »

Medium to dark roasts are easier to extract as to whether or not it benefits with flow or pressure profiling opinions will vary.

If you wanted to try, a profile copying what a lever does is a good idea. You start at high 8 or 9 bar pressure and decline as the shot progresses to reduce bitter and astringents. A constant 6 to 7 bar extraction could work too. Add in dropping temperature to 190 or lower and that's more than a few factors to play with. Sometimes though a dark roast is cooked to oblivion and unsalvageable.