by Jeff Miller of Artisan Family of Wines (Seven Artisans, Sly Dog Cellars, Red Côte Rosé)
When I couldn’t find out much about submerged caps, I started experimenting. I started playing around with using submerged cap in very small vessels, one that resemble small plastic trash cans, though they are food grade and made for grape/wine processing. When I was able to accomplish this with success, I moved on to macrobins. Macrobins are plastic bins roughly 42×42 inches square and a few feet tall, and are used to collect and transport the grapes to the winery. Often, especially when tank space is in short supply, the must will be pumped to macrobins instead of tanks, and fermented there before getting pressed off. After some initial failures, I succeeded in my attempt to devise a system to keep the cap submerged in a macrobin. This allowed me to compare the results of the submerged cap system with the results of a standard punch down (the normal method used in macrobin fermentations). Using a spectrophometer, I was able to confirm that the submerged cap wines were darker. While I got some outlier results, the average seemed to be about 15-20% darker for the submerged cap over the punch down.
But only a relatively small amount of a winery’s production is fermented in macrobins. The “holy grail” would be to devise a system that would work in a tank. I have a 6000 gallon open top fermenter, so last year I tried out a system to keep the cap submerged. The plan was to have fabricated a screen made from a food grade plastic sheet with holes in it anchored at what I computed to be the correct height. Unfortunately much of the cap succeeded in forcing its way through the screen, creating two caps, one below the screen, and one above. Getting the two caps out of the tank at press time was no fun (I succeeded in personally avoiding most of this work, but those that did it weren’t too happy with me). But as someone once said, every time I fail I learn another way how not to do it.
The screen used to keep the cap submerged, photographed shortly after the tank was emptied for pressing.
This year I devised a similar system, but one with much smaller holes using netting. I’ve attached a picture. Certainly, for those enamored of the “romance” of winemaking, you wouldn’t want to hang this on your wall, but it in fact worked pretty well.
I had set a aside one macrobin of the pretty much the same (unfortunately not exactly the same) grapes, which got the usual punch down treatment. I ran spectrophotometer tests comparing the submerged cap vs. the punch down, and found that the submerged cap was between 30-40% darker, depending on the exact wavelength. (Anyone interested in more detail, drop me an email.) I suspect that this overstates the benefit resulting from the submerged cap for reasons not worth relating, but am pretty convinced the submerged cap accounted for a large part of the difference in color.
My working assumption is that the amount of color extracted from the skins is going to be a pretty good indicator of the amount of other goodies (i.e., flavors) I’m getting as well. Unfortunately, that’s more of a working hypothesis than anything I can prove, though it seems reasonable. And color for many wine drinkers (including me) is a positive in and of itself (so that even if I’m not getting more flavor, just getting the additional color is a big plus).
Trying different things out in the vineyard or winery tends to be a humbling experience, as so much doesn’t pan out. So I’m feeling a little upbeat that this trial, several years in the making, seems to be, at long last, giving good results.
Jeff
Fetzer had some 5 ton tanks fabricated that have a metal screen welded about a quarter of the way down from the top of the tank. The inlet for the must line is below that. Wayne Burgstahler makes a screen for 48S bins that clamps to the sides with thumb screws allowing the cap to remain submerged.
Very good posting, especially then learning curve in designing a screen / net that works. Glad to see someone else doesn’t give up on the first try. On your hypothesis that the increase in color also correlates with an increase in other goodies, I would hesitate to say that, because many of the compounds might not follow a linear extraction curve, and many of them might follow a complex extraction curve as they might be polymerizing or reacting with some of the microbes or chemicals in solution. I would bet that the most direct relationship to your spectrophotometer readings would be with anthocyanins. Even those might show a non linear relationship as they might be polymerizing with tannnins. I don’t know, I’m just a internet dork posting on a blog comment. But I did really like your 2 part blog. Thanks
I agree that there’s no way to know that the color as measured by spectrometer necessarily correlates with other things in the wine that we want to extract (or maybe don’t want to extract). My inquiries as to what else to measure and how those other substances would effect the sensory impact of the wine left me feeling that that there wasn’t much worth doing besides the color tests (though if someone feels there are other measurements that would be of value, i would ask them to post a comment). My subjective view is that a more colorful wine is also a more flavorful wine, so I feel comfortable that color matters.
Crikeys! This is a lot of (intellectual?) contrivance.
Why not taste the goddamn stuff in six months against a control-group before assuming squid-ink is the second coming.
Why would you ever want to ferment a quality red wine in a closed tank? If suspended caps mean pumpovers why would you want to do that? The winery of the future will only make red wines in T-Bins or Macros. Push downs are amazing and it so important to have your hands in the must 2 or 3 times a day and be tasting. We need to get rid of these silly UC Davis Factory Farm wine techniques.
I see absolutely no reason not to ferment in a closed tank. The only thing an open tank does is allows oxygen into the wine, which, at that point, is definitely something you want. But you can get oxygen into the wine in a closed tank in various ways. Getting the oxygen in is what counts, not how it gets in.
This idea has been around for awhile. Following is a link to a YouTube video about Chaim Gur Arieh’s Submerged Cap Fermentation system which he has been developing over the last eight years. This system makes very elegant yet highly extracted wines.
http://www.youtube.com/watch?v=4f0cfbefuk0&feature=player_embedded
Chaim has been making wine with a submerged cap for over 9 years - he has custom made tanks which are worth a look. They are in the Foothills - winery in El Dorado and a tasting room in Amador.
Chaim Gur-Arieh, Ph.D. Winemaker/Proprietor
Cheers!
Interesting blog!
My primary reason for pumpover or punchdown is to manage the temperature. The area under the cap can get pretty hot while the bottom of a fermentation can be much, much cooler. Any idea about the temperature of your trial fermentation at various points in your tank? Higher temp can lead to higher extraction.
I find it interesting how CSW’s declare themselves experts in wine production. This is an interesting article on submerged caps. Kudos to the hard working author of this trial. As far as closed vs open top tanks go, I’ve worked extensively with both and though it may seem to “wine geeks” like a much higher quality practice to produce in open tops, I assure you it is not. These silly somm education classes need to include harvest experience to round out the inaccuracies in their educations and misconceptions.
I set the chiller on and keep the temperature at 75 maximum. That, of course, is the temperature at the tank’s thermometer. Obviously there will be some variation at different parts of the fermenting must. Sorry, but I don’t have any information on what the tank temperatures were except from the tank thermometer. My main concern about higher temperatures is the heat buildup in the dry part of the cap, which can foster microbes. Obviously, to the extent the cap is entirely submerged, there is no dry part of the cap, which seems like it would help keep the fermentation clean.
As long as you’re getting oxygen into the fermenting must, I can’t see how a closed top system is inferior.
Have you considered swapping out your wine punch-down with the pneumatage process instead?
It’s by far the the best way to automate your cap management in single or multiple tanks and also efficiently aerate you juice during fermentation to eliminate the formation of hydrogen sulfide and mercapatans
http://www.pneumatage.com/
http://vimeo.com/6594151
Very nice article. I thought to let you know that you website wasn’tt getting displayed properly on skyfire browser on my pda.
Have a nice time…sorry for typing mistake
Too funny, because this CSW/luxury winemaking consultant knows more about wine and making wine than a few hundred goon winemaking kids from UC Davis and Cal Poly ever will. You can’t teach taste. Push downs are about the expression of full vineyard flavors and excellent mouthfeel. Pumpover make average, dull and flavor substandard wines. Don’t make your wines in dairy containers. Pumpovers are for two buck chuck. The best winemakers are actually making their red wines in barrel. The smaller the better. If your going for high profit boring wines than please by all means do your pumpovers and make more homogenized, grocery style wine. I am happy when my clients wines are ten times better than yours, lol. Please continue, it makes my job wayyyyyyy easier. BTW you should learn how wine is supposed to taste before learning how to make it.