I have been experimenting with brewing medium roasts in my french press.
Contrary to popular advice, I have found that grinding on my Baratza Encore’s grinder finest setting of “0” gets me a better brew than the traditional advice of settings 20 (middle) to 40 (coarsest).
The resulting grounds were somewhat smaller than supermarket ground granule size, eyeballing about 1/2 to 2/3 the size. Certainly nowhere near espresso-powder fine.
With the finer grounds, I brew for 3-4 minutes with my hot water at 195F/90.5C, the default for my Zojirushi hot water pot.
I have tried this with both a whole bean local roast, and a bag of nearly-expired supermarket house brand grounds that was on sale for $5.
The local roast yielded smooth taste with bright and pleasant fruity notes from a shorter brew of 3 minutes. The house brand, umm… the finer grind improved the taste.
I theorize that re-grinding the old house brand grounds exposed volatile flavor compounds that hadn’t evaporated or oxidized yet.
A 4 minute brew with the local roast was too long, and resulted in astringency.
4 minutes of brewing with the old house brand was only slightly astringent, but much better than the weak sauce at 3 minutes.
As with anything on the internet, YMMV.
p.s. I’m an impatient bastard and I’m not willing to wait 8 minutes for James Hoffman’s Ultimate French Press Technique, which I find doesn’t result in a better tasting brew anyway.
I think the idea of using coarse grounds for the French press is mostly for filtering out the grounds with the steel mesh on the plunger. If you have a finer mesh, by all means, go for it.
I’ve also seen some of my fellow coffee lovers at work use filters wrapped around their press, or using an ultra-fine metal mesh on their air press. They’ll go for a finer grind, and it definitely helps the brew steep quicker.
Personally, if I’m using a glass press, I can usually tell the brew is done by jostling the pot and seeing if the grounds sink. In my metal one, it’s usually 5+ mins, and then it’ll jostle and test the resistance with the plunger to see if the grounds sank.
I concur that the built-in mesh filters in all but the most expensive french presses are crap.
I strain the brew out of my press through a fine mesh filter.