Joe,
Initially, I should say I do not sterile filter all wines - only those where I have stopped the malo or those I feel would otherwise require it.
When I do, I cross flow in the winery (which is nominal) and sterile in the bottling line (absolute). Personally, I do not see why one would Velcorin if this regimen is followed. As a matter if fact, I think this an alternative to Velcorin - but I leave lots of room for other opinion on that point.
As for dissolved co2, one can make an adjustment prior to cross flow if that is something one wishes to do. In your case, it looks like you have nothing to fear from cross flow vis a vis co2.
Before I decided on cross flow, I did a lot of taste testing and, as mentioned above, have yet to come across a wine that I thought suffered significantly. But taste is so subjective I think that anyone considering cross flow might want to try a little tasting before hand to see what they think.
Best, Jim
Off topic, but if you want to add CO2 to a wine then bubbling ‘beer gas’ through the wine is an easy way to get a complete/uniform mix without too much CO2. Beer gas is a mix of Nitrogen and CO2…there are various mixes available, but 75%N/20%CO2 (stout gas) and 60%CO2/40%N are common. Bubbling the N will reduce the CO2 (and O2, of course) in solution, and (obviously) bubbling CO2 will increase the CO2 in solution. So bubbling beer gas will give you an equilibrium of CO2 in solution…no matter how much beer gas you bubble. The higher the % of CO2 the higher the equilibrium level will be. I haven’t done this myself (I’m generally trying to lower CO2 levels before bottling), but a friend has done this a few times. Apparently stout gas (75%N/20%CO2) is best as it doesn’t come across as spritzy.
I cross flow filter about a week before bottling and then sterile filter at the bottling line and do this for all my wines whether or not they have any residual malate or sugar. I do this out of convenience and lack of confidence, because when the bottling truck is here, the sterile cartridge is in place (since it is used for some whites which do have residual sugar). So once it is in place, I just run everything through it.
I am rethinking my policy and it is interesting to hear what others are doing, pros and cons.
Thanks.
Thats quite interesting and definitely something I have not thought of. I have never had to add any co2 to our wines but it is something we watch to make sure there is enough of in the wines.