The Ganimede Fermentation Method: How Does It Stack Up to a More Traditional Approach?

Part of the traditional process of red winemaking involves a maceration step, allowing the skins and seeds of the grapes to “steep” together for a certain period of time in order to extract the desired compounds that make up a quality wine.  If one just leaves the skins and seeds sitting in the wine and leave it alone completely, eventually all the skins will rise to the top, forming a hard, virtually impenetrable cap resulting in poor extraction, and poor yeast performance, just to name a couple examples.

What winemakers and cellar workers have to do to improve performance and optimize phenolic and other compound extraction from the skins and seeds to the wine, they must “stir up” the solution, punching down the skin/seed cap at the top and reintegrating it into the wine.  More extraction can occur, and then over time, the skins and seeds float back up to the top.  You can see then, this becomes a cycle of punching

Photo by Flickr user ryanovineyards (http://www.flickr.com/photos/mroconnell/)

Photo by Flickr user ryanovineyards (http://www.flickr.com/photos/mroconnell/)

down and mixing, which depending upon how it is done can be time consuming and relatively difficult.

One of the more recent technological advances to help improve maceration techniques is the Ganimede fermentation method, and is the focus of the study presented to you today.  Very briefly, the Ganimede fermenter consists of an inverted cone inside and toward the top of the device, allowing carbon dioxide to become trapped in the space between the cone and the side of the fermenter.  As fermentation goes along, the CO2 continues to build up until the pressure is high enough to be released through an external pipe that connects back to the top of the fermenter, effectively pushing the skin and seed cap back down into the must.  This is apparently a much more gentle method than physically punching down the cap with more traditional materials and equipment.

To learn more about how the Ganimede fermentation method works, you can check out their website here and look around.

Photo courtesy of Ganimede.com (see more: http://www.ganimede.com/en/mg_come_funziona.aspx)

Photo courtesy of Ganimede.com (see more: http://www.ganimede.com/en/mg_come_funziona.aspx)

How does the Ganimede fermentation method compare with traditional fermentation and maceration methods in terms of the phenolic profile of finished wines before and after aging?  Is the Ganimede fermenter as successful as traditional maceration in extracting phenolic compounds from the must?  How does a wine fermented in a Ganimede fermenter fare with aging compared with traditional methods?

As many of my readers know, phenolic compounds in wine play a major role in the overall quality and ageability of a wine.  From color to aroma and from astringency to body, phenolic compounds act both independently and in concert with one another to produce a unique wine with specific characteristics that set it apart from all other wines.

The article presented to you today aimed to compare traditional and Ganimede fermentation methods on the phenolic profile of Cabernet Sauvignon wines, also taking a look at how aging of these wines differed (or not!) depending upon which fermentation method was employed.

Methods

Cabernet Sauvignon grapes were harvested at maturity from a vineyard in Yuma, Ningxia province in China (2009 vintage).  After sorting and destemming, the grapes were separated into four different groups:  2 groups for the traditional winemaking treatment, and 2 groups for the Ganimede fermentation treatment.

For the traditional winemaking group, alcoholic fermentation was completed in a stainless steel tank, with maceration occurring simultaneously using pump over mechanisms.

After fermentation, both groups went through malolactic fermentation and later bottling.

The following compounds were measured and analyzed for all wine samples: total phenolics, color intensity, anthocyanins, flavan-3-ols, flavonols, hydroxybenzoic acids, hydroxycinnamic acids, and stilbenes.  Specific compounds included (+)-catechin, quercetin, gallic acid, caffeic acid, and resveratrol.

Results

Before Aging:

  • 22 anthocyanins were detected in wines fermented using traditional methods, while 23 anthocyanins were detected in wines fermented using the Ganimede fermentation method.
    • The extra anthocyanin found in the Ganimede wine was peonidin-3-O-(6-O-acetyl)-glucoside-4-vinylphenol.
    • In general, the anthocyanin profile for both traditional and Ganimede wines were very similar.
  • Anthocyanin levels in Ganimede wines were significantly higher than wines made using traditional fermentation methods.
    • Monomeric anthocyanin levels were significantly higher in Ganimede wines compared with traditional wines.
    • The anthocyanins malvidin-3-O-glucoside, petunidin-3-O-glucoside, dephinidin-3-O-glucoside, and peonidin-3-O-glucoside were significantly higher in Ganimede wines, resulting in a deeper red/purple color that is often considered desirable among consumers.
    • The authors indicate that these results suggest the Ganimede method may be more appropriate for younger wines, since anthocyanin levels were higher in these wines and it’s generally faster and less labor-intensive to perform Ganimede fermentation compared with traditional fermentation.
  • Wines fermented using the Ganimede fermentation method has significantly higher levels of acylatedanthocyanins compared with wines fermented in traditional methods.
  • There were no differences between the two fermentation methods in terms of anthocyanin polymer content.
  • 38 non-anthocyanins were detected in the wines.
    • Flavan-3-ols and flavonols were the dominant non-anthocyanins present.
  • Total flavan-3-ols were very similar between Ganimede wines and traditional wines.
    • (+)-catechin and (-)-epicatechin were significantly higher in wines made using the Ganimede fermentation method compared with wines made using traditional methods.
  • There was no difference in hydroxybenzoic acid levels between the two groups.
  • Hydroxycinnamic acid was significantly higher in wines made in traditional fermentation methods compared with the wines made using Ganimede fermentation methods.
  • Both trans- and cis-resveratrol was detected in both wines, while resveratrol-3-O-glucoside was only detected in the wine made using traditional fermentation method.
  • Stilbenes levels were significantly higher in wines made using traditional fermentation method compared with wines made using the Ganimede fermentation method.
  • The total polyphenol index of both wines was statistically similar (though technically the value was slightly higher in the traditional wines).
  • Color intensity was significantly higher in wines made using the Ganimede fermenter compared with wines made using traditional methods.

After 2 Years of Aging:

  • After 2 years of aging, 15 anthocyanins were detected in wines made using traditional fermentation techniques, while 17 anthocyanins were detected in wines made using the Ganimede fermentation method.
  • Total anthocyanin levels decreased with aging by 75% for wines made using traditional methods, and by 81% for wines made using the Ganimede fermenter, resulting in about 10% more anthocyanins in the traditional wines.
  • The ratio of pyranoanthocyanins and polymeric anthocyanins increased with aging in both groups, in addition to a decrease in monomeric anthocyanins (a benefit to color stability).
  • All non-acylated anthocyanins decreased in both wines, though they were significantly lower in wines made using the Ganimede fermentation method compared with wines made using traditional methods.
  • There were no differences in acylated anthocyanins between the two groups.
  • Pyranoanthocyanin levels were significantly higher in wines made using the Ganimede fermentation method compared with traditional methods.
  • Peonidin-3-O-glucoside-4-vinylphenol and malvidin-3-O-glucoside-4-vinylguaiacol were only detected in the aged Ganimede wines, resulting in a more yellowed color than wines made in traditional fermentation methods.
  • Polymeric anthocyanins were statistically equal between the two groups.
  • Total flavan-3-ols were similar between the two wines.
  • After aging, caffeic acid was significantly higher in wines made using the Ganimede fermentation method compared with wines made using traditional fermentation methods.
  • The total polyphenol index of both wines was significantly higher in wines made using traditional fermentation methods compared with those made using the Ganimede fermenter.
  • Color intensity of the Ganimede wines significantly decreased with aging, though the final levels were statistically similar between the Ganimede wines and the traditional wines.

Conclusions

Overall, according to the researchers, the results of this study indicate that while phenolic content of both wines were generally similar to one another, there were a few small differences that were significant enough to make marked changes in the finished wines.  Specifically, wines made using the Ganimede method had greater levels of anthocyanins and other polyphenols when the wine was young, showing richer coloring and overall improvement in the phenolic characteristics of the finished wines.  On the other hand, as they aged, the wines made using the Ganimede method lost a significant amount of anthocyanins and other polyphenols over time, resulting in an aged wine that was much less stable (at least in terms of color) than the aged wines made using more traditional methods.

If the results of this study are indicative of true, repeatable events, then it would seem to suggest that the

Photo courtesy of Ganimede.com  (see more: http://www.ganimede.com/en/mg_come_fatto.aspx)

Photo courtesy of Ganimede.com (see more: http://www.ganimede.com/en/mg_come_fatto.aspx)

Ganimede fermentation method may be the better choice if the goal is to make young “drink now” wines, while if the goal is to produce a wine capable of aging, traditional fermentation and maceration techniques seem to be much more appropriate.

Overall, I think this study did a nice job, though I would be hesitant to say that these results are repeatable for all wines.  First, the only grapes used in this study to make the experimental wines were Cabernet Sauvignon.  Perhaps these are the results one gets for Cabernet Sauvignon, but do we see the same behavior when we try a Syrah, a Sangiovese, or maybe a Merlot?  Due to phenolic differences between the grape varieties, I would like to see the same study repeated using multiple grape varieties in order to see how this Ganimede fermentation method affects musts other than Cabernet Sauvignon.

The other problem with issuing blanket statement on which fermentation method is better is related to the location in which the grapes were harvested and the wines were made.  If you recall, these grapes were grown, harvest, and processed in China.  What effect does Chinese terroir have on different grapes? (Here’s an article looking at the influence of terroir on Cabernet Sauvignon in China).  How does this compare with grapes grown in France, the US, Australia, or any other grape growing region?  Maybe using the Ganimede method is better for young “drink now” Chinese-made wines, but perhaps the results would be opposite if grapes from other winemaking regions were used?  Before I would say “the Ganimede fermentation method is better for young wines”, I would need to see results from multiple grape varieties grown in multiple grape growing regions.

What about you all?  Do you have any experience with Ganimede fermenters?  What were your results?  Please feel free to share any and all comments or questions you all might have related to this research/topic.

Source:  Bai, B., He, F., Yang, L., Chen, F., Reeves, M.J., and Li, J. 2013. Comparative study of phenolic compounds in Cabernet Sauvignon wines made in traditional and Ganimede fermenters. Food Chemistry 141: 3984-3992.

7 comments for “The Ganimede Fermentation Method: How Does It Stack Up to a More Traditional Approach?

  1. February 10, 2014 at 11:55 am

    Thanks for sharing – and certainly interesting information indeed. I had a chance to work with one of these fermentors nearly a decade ago at a winery here in the Santa Ynez Valley, and what I found was the the wines produced using this fermentor tended to be lighter in color and higher in ‘fruit intensity’ than similar grapes fermented with traditional pump over techniques, and the wines produced with the Ganimede tended to have less ‘structure’ at pressing. I did not follow these wines along during their aging, though . . .

    A couple of points here:

    It would be great to bring this information into terms that the general wine consumer can understand, because the terminology used in ‘wine research’ is quite valuable, but spoken in terms that don’t ‘jive’ with what consumers know about wine.

    Second, this type of research is ‘interesting’, but only N’s of 2 for each method really does not qualify it for much ‘statistical significance’. If the researchers really want to come up with more specific ‘results’, they should many more trials.

    There is no way to know if the ‘fermentations’ were identical in nature – how long each fermentation was; average and peak temperatures of each fermentation; cold soak times? All of these will have an impact on the results.

    Thanks again for sharing and hope to see more from you in the near future!!!

    Cheers!

    • Becca
      February 10, 2014 at 6:43 pm

      Hi Larry! Thanks for reading and for all your great comments and suggestions!

      You are right—I could have done a better job writing this more for the “lay person” and not so heavy on the industry side of things. That is my ultimate goal, but sometimes I get so wrapped up in the science that more scientific terminology sneaks in there and stays ;)

      I also agree with you about the low sample size. They did at least run each fermentation in duplicate, but still, that’s not enough to be all that convincing. Based on the comments that other have made (either here or elsewhere), it sounds like their results are in line with what other people experience, but I agree they should increase that sample size a bit more for some more power!

      Just keep reading and commenting, and I’ll be certain to keep supplying the material :) Cheers!

  2. Margaret Davenport
    February 10, 2014 at 11:56 am

    Lots of questions: frequency of punching down/pumping over during different stages of fermentation; temperatures each stage of fermentation and at different levels in the tanks (red ferments temperature stratify); tank height and diameter; tonnage of each ferment.

    • Becca
      February 10, 2014 at 6:50 pm

      Hi Margaret,

      Here is exactly what was written in the methods section regarding many of your questions (i.e. fermentation parameters for the traditional and Ganimede methods):

      “Alcoholic fermentation by the traditional method was carried out in stainless steel tanks of 40,000 L capacity at a controlled temperature of 28 ± 2 °C. Maceration was carried out at the same time during the fermentation by periodic pumping with aeration. During the fermentation, the musts were pumped by venture from the bottom of the fermenter to the top for 20 min every 4 h.

      The fermentation in a 45,000 L Ganimede fermenter was conducted at 28 ± 2 °C. This method produces an inert atmosphere of CO2 above the fermented wine and thus restricts air access into the fermenter. Time of the gas release through a by-pass external pipe depended on the density of the fermenting must. Before the must reached a specific gravity (SG) of 1.082, the gas valve of the tank was opened for 1 min every 4 h. In the middle of fermentation, the filtered air was pumped into the fermenter at a flow rate of 350 L/min for 1 min after pumping the CO2 for 2 min. The CO2 was pumped into the fermenter at intervals of 50, 40 and 20 min sequentially until the specific gravity dropped to 1.008. Then, the aforementioned procedure was repeated every 1 h for 1 day until the must was at 1.001 SG, then every 4 h for 1 day until at 0.999 SG.

      Once the alcoholic fermentation of both traditional and Ganimede method completed, malolactic fermentation by indigenous bacteria was adopted and completed later above 18 °C. Potassium metabisulphite was then added to the wines to reach the free SO2 at a level of 30 mg/L before the wine bottling. Then the wines were stored at 18 °C in the dark.”

      It was not clear to me what the height/diameter of the tanks were, but you can probably get a pretty good idea based on the volume listed above. Also, the authors did not seem to supply us with information regarding the tonnage of each ferment.

      Thank you for commenting with your questions, and I hope my response was somewhat helpful!

      Cheers!

  3. February 10, 2014 at 3:35 pm

    I work at a winery that uses Ganimede fermenters for all red wine production and it’s great to see an independent study about their effects on wine chemistry. All we’ve had until this point is sales literature from the manufacturer. I agree that they do reinforce the quality of the wines in their youth – much of our production is geared to be ‘ready to drink’ with lots of color, tannins, and flavor, but the tannins aren’t harsh or astringent at all which gives them a much smoother edge in a way. It’s fascinating. Thanks for sharing this Becca!

    • Becca
      February 10, 2014 at 6:53 pm

      Totally cool, Luke! I enjoy hearing about real-world applications of what’s studied in the literature, and it’s really great to hear that you all are having similar experiences/results as they did in this particular study.

      Thank you for reading and sharing your experiences with us!

      Cheers!

  4. October 21, 2014 at 7:48 am

    Hello, I think we should also consider the amount and influence of areation/oxidation on the various compounds in the traditional technique compared to the Ganimede method which, as staded before “produces an inert atmosphere”

    Thanks for sharing :) cheers!

What do you think about this topic?