Vertical Leaf Velo
We just got a new 3Sqm Velo vertical leaf filter. Ive only used a horizontal and am wondering what the main difference is. My old SOP was precoat with water blow down with CO2 and then bring beer in and go after a quick recirc. Im thinking this may not work with a vertical leaf as the DE might slide down the plates upon purging. Im going to try the initial run with a beer pre-coat which I have never attempted on the old unit. Also the same question about final blowdown, can you purge the last bit of beer w/ CO2 on a vertical model or do I just need to chase with water as recomended by Velo.
I've not used a vertical leaf filter as such, but lots of expereince with plate and frames. I really can't see that you could do anything other than precoat with beer or water, and leave this in constant forward flow or recirculation whilst you want to keep the bed on the leaves.
With cellulose sheets in a plate and frame, we have managed to keep the bed on if the pressure is released VERY slowly on the discharge side, but I suspect the finish on what I suspect is an all metal filter will not hold this at all.
So yes, precoat with water or beer, push out with beer and at the end push out with water, not gas. If you aim to brew a little stronger then you can afford dilution on start up and finish more easily to reduce volume losses - not overall extract losses. Only someone high gravity brewing with intentional post filter dilution can consistently reduce extract losses to a very low %age.
We work with a 10sqm Velo vertical...instead of pushing the water out with CO2, bring beer to the filter and push water out to drain with beer. Once outlet is predominately beer, simultaneously switch from drain to bbt's. At the end of run, put the Velo in recirc before the pump cavitates, introduce water to the filter and push the beer out with water.