So we filter our whiskies through a cotton sock filter to catch larger pieces of char when we harvest barrels, then chill it for a couple days, and then run through a set of four 1micron Aftek cartridge filters in a 2x2 series. When I first started using this method, I seem to remember a batch of whiskey (let's say ~1000L-1200L) taking a day/shift to filter, as we would experience some slowdown, but nothing terrible. Lately however, it seems like we experience such a strong jam in the cartridge filters that we have to actually swap them out before we can run the filtration with good flow again. This is why I'm sure it has something to do with the filters, though what it is exactly, I'm not sure. I've used both a diaphragm pump and an impeller pump. Whatever this issue is, would I be better off running 5micron to 1 in series, or maybe just all 5micron? We use a 1micron filter for our bottling line.
(Sort of a long story, but a lot of what we do is sort of a holdover from the previous team of people, but I'm the only one left from the old guard. I worked for a short time at this distillery, then up at a sister company for a few years, then came back to the distillery after a lot had changed, most importantly the staff, so there's no one here who really understands the methods behind the madness any more. Hence, I can't really troubleshoot some of our issues specific to our operation.)
From what I've been able to read up on, it would seem running all these 1micron filters might be overkill. I just want to clean the product in a timely and more efficient manner (i.e. use only one set of filters per run), and polish it right before it gets into the bottle.
As an experiment, we only ran with two filters instead of four before running through the bottle line, and I stuck a bottle into the freezer overnight. Cloudy. So running sluggishly with four filters was getting us our clarity, apparently. Out of curiosity, I'm sticking a bottle from an older run in the freezer now to see if maybe that's just typical for the product.
So again: can I solve the steep drop in flow rate by using 5micron filters instead of 1? Should I run all 5's, or 5's into 1's?