Hi all,

I just finished a bag of Intelligentsia Classic, which I had dialed in real nicely with my last shot at 11 days past roast... I was looking for something new and slightly more eccentric so I splurged on some Phil & Sebastian Honey//Panama. Holy crap that stuff is roasted light, significantly lighter than the Epic from 49th Parallel (which is saying something). Anyways, I've never ground anything this light since getting my SJ and was shocked how fine I had to go to avoid painting my kitchen cabinets with spray from the PF! This coffee was 3 days past roast vs 11 days of the Black Cat and I went about nearly 4-5 notches finer in order to get a decent shot. Still not dialed in but I'm drinking them at this point ($19/340g so I'm less apt to "sink" the shot if its palatable).

My question - I know lighter roasts require a finer grind due to their characteristics vs darker roasts, but I found myself asking what is actually going on. Do I need to set the grind to a finer setting in order to produce a similar particle size of coarser setting/dark roast? Or do the particle sizes actually need to be smaller with a light roast?

Don't know how much it matters... just was shocked into asking myself a question I couldn't answer and thought I would turn to the all-knowing forum!

Dark(er) roasts are more brittle and produce more fines.

Light roasts are harder to extract. Grind finer and run the shots longer than for darker roasts to ensure you hit a decent extraction yield.

JP

As mentioned, lighter roasts require finer grind setting and are harder to dial in. In addition to dialing in the extraction, make sure your distribution and tamping is on point to avoid that spray channeling.

I am guessing that fewer fines make for fewer blocked paths, making it easier for water to travel through the puck.

I find I need to have much hotter shots on light roasts so they are not sour.

T

Sourness is usually associated with under extraction

Light roasts are more acidic. Fast shots are more sour/acidic. So I prefer to have longer shot times for lighter roasts to balance out those factors. Light roasts are harder to extract more soluble content, when water is hotter, the molicules extract more soluble content because they are more active.

In addition to the fines theories, I imagine that lighter roasts are less soluble and thus require more surface area to get the good stuff out.

This makes me wonder about an experiment. Would a portafilter of similarly sized insoluble material (fine sand?) gush or provide similar resistance as coffee. I feel like the viscosity of the coffee being extracted probably has an effect.