I filtered my first home made yesterday. I remembered reading about the altered plunger and here it is. Very useful. I just used it to filter out the raw output and poured the juice straight into a coffee filter. But I sure managed to squeeze the hell out of the tobacco.
I'm curious about the felt. what kind,.. do you place it between the bottom plate and the filter mesh?
Now even a good french press isn't made to handle pressure on the sides (the exterior of the disk, unlike a syringe), don't you think most of the particulates manage to find their way on the sides where there is minimal pressure?
Polyester felt filter with a pore size of 5 microns. From McMaster-Carr online. I've posted a link about ten times in the various home extraction threads, no doubt it's in this one somewhere over the past two months.
Yes, the felt filter goes between the wire mesh filter and the metal plate. When the plunger is reassembled, everything is screwed tight and held in place securely.
I cut the 1/8" thick poly felt slightly larger than the diameter of the wire mesh filter on the plunger of the French Press. That way, when installed behind the wire mesh in the plunger, the poly felt forms itself against the inner wall of the glass carafe. The pressure against the sides of the carafe is snug, but not nearly enough to crack or shatter the borosilicate glass. I'm very careful and slow in plunging, however. The filtering process is visible initially, so I can tell you with certainty that very little if any liquid from the maceration suspension/slurry comes through at the outer edge of the poly felt. It comes right up through the middle of the filter pad disk. That's even more obvious when I rinse out the filters afterwards.
When I first thought of using the French Press with an extra, much finer filter, I figured it would probably be a bust and either work badly or not at all. But I was wrong, happily. It does the job beautifully. If this method didn't work, I wouldn't have left numerous posts about it. I'd have posted "back to the old drawing board" once and simply moved on.
I don't know for sure if the French Press plunger method would work as well with a filter finer than 5 microns. Maybe, maybe not. Grade 6 Whatkins filter paper is 2.5-3.0 microns, but in the 9cm diameter, it's pricey, so I'm not going to find out. Anyway, I'm happy with the results at 5 microns, and the 3' by 6' sheet (minimum order size) of poly felt I bought for $20 shipped will be enough to last me forever.
All NETs will gunk up coils and wicks eventually, but the extracts I've filtered this way---15 so far---are notably clean in performance while still providing flavor that's ample and rich.