Problem: Dark Roasting

Can you give some recommendation how can dark roast be brew if:
I have no refractometr and scale
I using La Marzocco DB 5 and Mazzer Robur (not electronic)

I need one thing - put the bitter taste down and find some sourish

General rule of thumb for me, 13:1 brew ratio with larger grind size than for medium roast. Adjust brewing technique to elongate brew time. Also required to not use water temp higher than 193 degrees Fahrenheit.


Thank you. But: as i said, i use La Marzocco - I mean, my espresso too bitter.
In the same time idea about low temperature looks good
But 193 degree - isn`t it too low if we talking about espresso?

Apologies, I was discussing brewing coffee, not making espresso.

I have not heard of making espresso with “dark” roast, as such. I am wildly guessing, but need to pull a 20 second shot, lower volume, increase grind size all to slow extraction. Don’t adjust temperature down unless other changes can’t fix.

But… this really outside of my experience.

Dark roasts, due to being lighter in density compared to medium will extract much more quickly. Because of that, need to adjust as above.

Thank you)

Actually, it`s could bring a problem for me - bring into alive your recommendation)

Because i`m working at commersial coffeehouse.

They have own standarts - they used volumetric standart, time of extraction, dark roast and they use 4 external attribute of “good” espresso and none a word about taste )))

My knowledges is not enough, but i`m here like a training manager… )))

So, i try to do best from these poor things, wich my employeer gived
Big brands - full of headpain, when you try to give quallity. Espacially at my state.
Well, thank you for your help, i`ll doing all, what you said)

Good luck! There is a lot that can be done with darker roast.