Bottling day should be spent making sure that the right product is going into the right bottle with the correct label and closure. It's imperative to monitor all of the technicalities that come with these steps. If you have to correct filterability in-line with bottling, do so with a lenticular housing and not a sheet filter. Sheet filters require full attention from the technician and aren't designed to handle the stops, starts, and subsequent pressure spikes on the bottling line.

Use this checklist as a guide to ensure a successful, stress-free bottling day.

 Filter through a Seitz EK (0.45 micron) or at the coarsest a Seitz KS50 (0.5 micron) sheet or lenticular or crossflow within 24 hours of bottling. For sweet, colloidally dramatic or historically difficult varietals, try to filter within 12 hours before bottling. If you have to wait longer, consider filtering through a Seitz EK1 (0.35 micron). This timed prefiltration prepares the wine to smoothly and successfully get through the 0.45 micron final membrane cartridge on the bottling line.

 Please note that adding sugar, concentrate, gum arabic, tannin, mannoproteins or blending different lots together after this final depth filtration may result in filterability failure (clogged bottling cartridges = imminent) and you would need to re-filter through EK or crossflow to correct it. Read the instructions on your gum arabic, tannin, mannoproteins, and CMC products – some of them are added 48 hours before bottling. If you add anything to change the colloidal status of your wine, you need to retest filterability to confirm or refilter.

 After the final depth filtration, adjust your SO2. Do so at least 6 hours before bottling. Large SO2 additions prior to bottling not only gives you a higher likeliness for prolonged bottle shock, but it can shrink microorganisms and they can potentially get through the membrane and cause problems later.

 Adjust your DO (dissolved oxygen) to <0.5ppm and CO2 levels to <1300ppm. Too much CO2 can push out the cork and/or make them leak so check on specific limits with your cork/cap supplier. Nitrogen can be used to scrub both dissolved O2 and CO2 to acceptable levels.

 If you’re using cartridges that you stored in an acid/sulfur solution or ethanol (inexpensive vodka), take them out, inspect them, rinse them well and test their integrity to make sure they’re still good. Change O-rings if you forgot to take them off before storage as they may be stretched out or cracked.

 Make sure your bottling line is cleaned and sanitized properly and use ATP bioluminescence swabs to confirm the absence of biofilm.

Most importantly, enjoy your bottling day – don’t stress about filtration!