I’ve just come back from Epernay where the biennial VITeff trade show was taking place. All the usual suspects were there: manufacturers of tanks, presses, pumps, packaging/labelling, and bottling lines, in addition to vineyard equipment and vine growers, and more.
Wednesday being the “Winemakers Technical Day”, I attended a conference on the filtration of white wines and, more specifically, of Champagne wines. The goal of filtration is to obtain a clear, sediment free and microbiologically stable wine.
Wines do not have to be filtered – it depends on the kind of wine produced. For example, in the case of either a red or white still wine barrel aged for 18-24 months, filtration may not be necessary before bottling: solids and yeast/bacteria might have all settled sufficiently, resulting in a clear wine that can be bottled as is. As an alternative, or in addition to filtering, winemakers can also use fining agents to help clear the wine of undesirable components.
With regards to sparkling wines, the base wine first goes through a primary fermentation, possibly a malolactic “fermentation”, and cold stabilisation. These processes generate a lot of solids including yeast, bacteria, and crystals that need to be removed by filtration prior to tirage (when a base wine is inoculated and bottled for secondary fermentation).
You might wonder: what happens to the solids after the second fermentation in the bottle? During tirage, we include adjuvants that help particles to settle and aggregate in the bottle, making riddling and elimination of the sediments by disgorging easy.
Deciding on the filtration method and medium is not always easy, since not only each vintage but also each “batch” of wine are different. From experience, one learns when and how to filter, bearing in mind that bench trials and experimentation help pinpoint the final setup.
Each method of filtration has its pros and cons, and methods might need to be combined in order for the winemaker to get the expected result. I will not go into detailed descriptions today, but here is a (short) list of some of these filtering media: D.E. (diatomaceous earth), cellulose, polymeric membranes, ceramic…
At the VITeff conference, one manufacturer unveiled a new high-performance cartridge filter, adding to the list of options available to winemakers.
I was also able to view this Pierre Guérin egg-shaped tank which is the only one of its kind for the moment (some exist in concrete or oak, but not in stainless steel like this one).
It is a bit pricey, but the buzz a statement cellar piece like this can generate amongst the winemaking community is priceless. Plus, maybe it’s cheaper by the dozen!
Jonathan Médard – Winemaker