I've been vaguely interested in sieving coffee grinds for awhile now, with some roots of that in the TGP and related discussions, as well as the look at the Baratza Vario grinder. I've always been rather bugged by the silt in my French press coffee, and while there are various methods to ameliorate this, it strikes me that though these methods make a marked improvement, in theory don't solve the problem of 'extraction differential' from steeping bimodally distributed coffee grinds entirely. Can your cup get cleaner? Would this allow you more flexibility with brew ratios/brew strength?
My first real interest was sparked by David Walsh's post about brew ratios, the commonplace occurrence of 'up-dosing' in traditional coffee brewing among specialty coffee professionals, and fines produced by most burr grinders, particularly consumer grade ones. Be sure to read the comments from James Hoffman/Nick Cho and David's responses; they clarify his article pretty well. This was David's superficial head-turner for me:
David Walsh wrote:I've heard it mentioned that the fines add complexity, I would argue brew a cup of 100% fines and see how complex you find it. A turd in a swimming pool probably makes the swimming pool more complex. It seems natural enough therefore that those of us sensitive to these types of flavours , identifying them as undesirable will perhaps instinctively move to coarser grinds that produce fewer fines. When we find the mouthfeel and body lacking we increase the dose.
David's article mentions the Brunopasso MPS-50 (MPS=Micro-Particle Sifter, I believe), a cool Japanese contraption for easily sieving grinds. I believe you can accomplish something similar (albeit dramatically less usable) with a tea infuser if you want an on-the-cheap, very soon solution; I have no idea where else you will find the MPS-50 other than Avenue 18, and I believe they are out of stock till mid-January.
In any case, after months of having this idea on the back-burner (technically, it still kind of is), I got one for myself earlier this month, and it arrived late last week. I've only just begun to play with the thing, but for starters, when sieving grind samples from the Vario in the range between about 2 macro notches finer than 'filter' all the way up to the coarsest settings, I see a loss by weight of about 10-30% (higher at finer settings). The 'micro-powder' is truly fine, rather finer than an espresso grind to my fingers.
I haven't taken David's advice and brewed with 100% fines yet, but I have been messing around, just a very little bit, with siphon brews and cupping of the larger particles after sieving. The siphon brews are interesting; even at pretty fine grinds, the draw-down time is as fast as you could imagine, not unlike a plain-water draw-down. I haven't been able to do any side-by side comparisons of those brews, but I did a little cupping with a fellow coffee enthusiast on Sunday, just brewed 2 pairs of samples of Black Cat (the only coffee I had on hand that wasn't on reserve for the holidays) at the same grind setting, with one pair sifted. No blinding or anything like that, though I don't think it would have been necessary--VERY different cups of coffee. The sifted samples were dramatically cleaner, maybe a bit in mouthfeel, but mainly in taste. Going back and forth, it really amped the sense of grainy bitterness from the unsifted samples. Yet, it wasn't a total wash that one was better than the other. The unsifted samples came off badly at first, but as the samples cooled the chocolate/aromatic wood flavors emerged from that sample, an element that, while it was rather muddied in the unsifted samples, was comparatively absent from the brighter, clearer sifted samples. I'm guessing they were under-extracted, but I have no idea.
As I alluded to in this thread, looking some more at this thing is something I hope to do while visiting family over the holidays, with my captive audience of a few extra coffee drinkers. In the mean time, I am curious if there's some more wisdom on this topic that I've missed out on, or if any other HBers sieve their brews before adding water.