“Why is it necessary to add the fining agents (package #4) before transferring the wine must off the sediment that has built up in the carboy bottom? Wouldn’t it be more efficient for package #4 to be added after the sediment has been removed?”
It seems the clearing agent has to do more work to clear the wine by adding it with the sediment still in the carboy, especially when you’re stirring this sediment up in the process. This one fools a lot of people, as it does seem at the outset that you’d want to get rid of the sediment first and then add the clearing agent, particularly when the wine in the carboy otherwise seems clear. The temptation is so great; many winemakers DO switch the steps themselves. This is not wrong – it’s just less efficient, believe it or not.
The clearing, or fining, agents used in WinExpert’s wine kits, whether it be chitosan or isinglass, both act more efficiently in clearing wine when they have a base of sediment to begin with. The sediment acts as a trigger mechanism which sends the finings into action in clearing out the mix of proteins, pigments, phenolics, dead yeast, etc. Both the fining agents and the particles to clear out from the wine have either a positive or a negative charge. And just like in the movies, opposites attract.
A negatively charged fining agent like bentonite will serve to bring together those particles having a positive charge, while positively charged fining agents like chitosan or isinglass will attract negatively charged particles. This process allows for the molecular weight structures of the particles to become larger: smaller particles join together to become larger particles, which in turn fall to the bottom of the carboy when their mass becomes great enough. If the fining agents do not ‘find’ enough particles present in the wine must to join together into larger particles, the clearing process may stall, as there will not be enough small particles present to conglomerate into the larger particles which will fall out. Small particles on their own will remain suspended in the must, and the fining’s efficiency is reduced.
This is why you must thoroughly stir the sediment when adding package #4, as it effectively mixes the fining agents and the particles together to start the clearing process. Resist the urge to jump the gun on transferring, or racking, the wine (unless it is required for that specific style of kit).
Other tips to consider in clearing:
- Removing the CO2 gas is a key part of the clearing process, as the dissolved gas can attach to the fining agents, preventing them from settling out. Prolonged whipping with devices to remove the gas may oxygenate and flatten the wine`s character. The use of our Vacuvin system or our Home Vintner degasser to do this without damaging the wine is recommended.
- Temperature is important, with fining agents working best in the 18-24 C range. Below 17 C they may stall.
- Never DUST your carboys as it can create a static charge that causes the particles to adhere to the sides of the carboy.
In a clear white wine, you should be able to read a newspaper through the carboy. In a clear red wine, use a bright light on the opposite side and check that there is no haze. (or thief a little into a glass and test with a strong flashlight). Last but not least, patience!
Trust the method behind the madness of WinExpert’s instructions, and stir up that sediment with confidence!
(Originally posted 2009, updated 2016)