Continuation of “The First of It’s Kind” Blog Post
The Wine Geek
So by choosing this option, you have professed that you are a wine geek! Embrace this fact that the details of making wine excite you, and learning about crossflow filters allows you to enjoy wine even more. (If you’re interested, I have the name of a phycologist who can help you with this issue!)
Any discussion about a crossflow filter needs to start with a basic understanding of filtration. It is possible to bottle wines unfiltered (like Madroña’s Single Vineyard Collection), but there is an inherent risk to this. The winemaker must be sure that the wine has completely finished its primary fermentation (sugar into alcohol) and its secondary (malolactic) fermentation. If one or both of these fermentations has not yet completely finished, it is possible that they would finish in the bottle of an unfiltered wine. The result is a slightly sparkly, turbid (cloudy) wine with some funky fermentation aromas.
So, most wineries filter their wines for stability reasons, especially if they plan to sell the wines to restaurants and stores (where storage conditions vary considerably—adding to the risk). Traditionally, wineries filter through a dead-end filtration, plate and frame system. Wines are pumped through pads of different porosities to remove solids, yeasts and bacteria.
With a Zinfandel being bottled after 11 months of barrel age (and two rackings), I would generally filter through a set of 3-micron pads to one tank and then a second set of 0.8 micron pads to another tank before bottling through a 0.65 micron membrane filter on my bottling line. Unfortunately, choosing the right number of pads with the right porosity isn’t really a science but more an educated guess. So sometimes we choose incorrectly, with the wine sailing through the pads (and not cleaning up the wine at all). Or worse, I choose a pad with too tight of a porosity (pore size) and the pads plug (or rather all the pores plug with solids, etc.) before the filtration is finished. And then I need to filter again for the same result. Over 40 years at Madroña, some combination of the two has happened way too many times!!!
Although the filter pads can be conditioned well enough that you can’t taste the “pad” in the wine, pad filtrations can “beat-up” the wine, making it necessary to age it longer (for the wine to recover). And generally, wineries keep wine movements to a minimum (tank to tank) as the wine runs the risk of losing fruit characters each time it is moved.
So why a crossflow filter? A crossflow filter uses a different technology. The basic makeup of a crossflow filter is a membrane with small capillaries (with very fine, 0.3 micron pores) running through it. The wine is pumped tangentially along these capillaries at a relatively high speed. Thus the inside of the capillary has a lower pressure than the outside. As wine is pumped along the outside of the capillary, wine “clean enough” to make it through the small pores inherently goes through the capillary to the lower pressure side. Solids (and yeast, etc.) and anything too large to fit through the pores stays on the dirty side of the capillary.
But unlike pads that simply plug the pores, the rapid speed of the wine being pumped by dislodges or stirs up this “sediment” and keeps it from plugging the capillaries. Every 10 minutes or so, this “dirty” wine is pumped back into the original tank for refiltering while the clean wine (through the capillaries) moves to the receiving tank.
In the end, a wine (no matter how turbid or cloudy) needs to be filtered only once, and it will be ready to bottle through a membrane on the bottling line. Fewer filtrations, fewer movements, softer processing and guaranteed success made having a crossflow filter our whole winery’s dream!
The Crossflow Special
To make this happen, Maggie asked me how I planned to pay for the majority of the $50,000 price tag. With the success of our pump sale a couple of years ago, we found out that the greater Madroña family (you all) had an interest in being a part of helping get specific pieces of equipment for the winery. There’s a sense of ownership as well as the thought that with each sip of the special wine, people have made something possible that maybe would not have happened.
I intentionally hold several wines back for rerelease later in their lives knowing that 1): the additional cellaring will only improve the wine, and 2): we have the responsibility of cellaring the wine (since most people don’t hold onto wines once purchased).
The wine of choice for me for this crossflow purchase is our 2009 Signature Collection Zinfandel. A warmer year produced a big, full-bodied Zinfandel with plenty of ripeness and wonderful structure. The purpose of a few more years of age on this wine is toning down the ripe fruit characters (allowing the subtleties of spice and earthiness to come through) while showcasing the suppleness and luscious texture of a great Zin (with cellaring).
To entice you, our greatest tasters, to support this effort, we are offering our employee discount (50%) to all of you on purchases of full cases of this Zin. Normally, at the $26 pricepoint, a case of this Zinfandel (non-aged) is $312. With the Crossflow Special, you’re looking at $156/case (+tax, of course).
Although I didn’t hold onto enough of the 2009 Signature Collection Zinfandel to pay for the entire crossflow filter, we can get most of the way with your help. We started showcasing this special (and tasting the wine) about three weeks ago in the tasting room. With only that exposure, we’ve already sold through half of my inventory. So time is short and we’d love your support.
Thank you for being a part of the Madroña community!