Postscript on Submerged Caps, the Subject that Just Won’t Die

by Jeff Miller of Artisan Family of Wines (Seven Artisans, Sly Dog Cellars, Red Côte Rosé)

jeff-smThere’s an old Dan Hicks’ song, “How Can I Miss You When You Won’t Go Away”.  Submerged cap fermentation seems to have taken on a similar life of its own.  At any rate, I think this will be the last post on the subject, at least for awhile.

What brought this subject back to life was a study I found published in 1961 in which Prof. Ough at UC Davis ran some tests on a submerged cap versus traditional pumpover and punchdown fermentations, and failed to obtain the increased color that I did.  In fact, he concluded that submerged cap fermentations resulted in less color, not more.  I don’t have a clue as to why he obtained results so different than mine.  At first I thought that maybe I’d done something very wrong since UC Davis, having the advantage of better equipment and real scientists, must be right.  But the more I thought about it, the more sure I became of my results, for a number of reasons.  For one, the tests that both Prof Ough and I conducted were similar in nature, so UC Davis probably didn’t have much of an advantage in this regard.  Second, on many of the samples, the extra color was visually apparent to the naked eye, so it’s hard to question spectrometer results to the same effect.  It’s possible that there was some difference in how Prof. Ough and I did our fermentations, but if there was anything that would account for our different results, I sure couldn’t figure out what it was.  So, at this point, it’s something of a mystery.

Prof. Ough also found that the cap temperature of the submerged cap was higher than in traditional fermentations, something I find quick surprising.  Since I didn’t think to try to measure the temperatures in the caps (both submerged and non-submerged), I have no evidence to question this conclusion, though next year I think I’ll try to remember to take some temperature readings, and see if I agree with him.

If anyone else has tried to do this sort of color analysis, I would appreciate any feedback they might provide.

For those interested, the Ough study can be found at

I also found these web pages in which the use of submerged caps was discussed:

Sangiovese: Varietal Focus (discusses the use of submerged cap fermentations at Viansa Winery for their Sangiovese)

Harvesting in the Priorat: Fermentation I - Maceration Techniques

Gur-Arieh’s submerged cap fermentation tank

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9 Responses to “Postscript on Submerged Caps, the Subject that Just Won’t Die”

  1. Matt says:

    The one thing in your post I will take contention with is “UC Davis, having the advantage of better equipment”. Until this last year, they did not have better equipment than most wineries, and in fact have been doing most of the fermentation research in old, poorly designed facilities. The buildings they have been using are over 125 years old, and most of the equipment has been donations. Lastly, some of the data comes from students performing pumpovers and such, which can be a huge variable.

  2. I like to figure out what UC Davis is teaching and then do the opposite, lol. Quality has never been a goal of theirs. How about surface area. I’m starting to feel that this maybe the most important difference in quality between push downs and pumpovers because of total surface contact area between the juice and skins. perhaps the surface area ratio in their test was smaller than yours. I know ridge pumps over its open top submerged 3 ton fermentors and and splashes the wine once a day during ferm to get more oxygen into the must. They also push down manually once a day to get oxygen in. It seems their might be more varibles do you think? Robert O’Maoilriain Sonoma Wine Critic,

  3. Thanks for the blog post. First off, I know that UC Davis is an ‘easy target’ these days, but let’s discuss a few things:

    You said that the paper from Ough that you were looking at was from 1961 . . . 1961! That was nearly 5 decades ago - and he was doing research that few others were doing at the time. Could it be that your results will be different than his? Of course . . . And could it be that the equipment you are currently using is as ‘advanced’ as his was 50 years ago?!?!? Most likely . . .

    Let’s also discuss seeing color ‘with the naked eye’ vs with a spec. I have often been fooled by what I see ‘with the naked eye’ vs what I am able to ’see’ with a spec - How do you ‘calibrate’ your eyes to be objective? Just a thought . . .

    And Robert - UC Davis’s program certainly DOES teach quality - quality by making sure you understand the processes from a theoretical and somewhat practical level - and quality from the perspective of understanding chemically and microbiologically how to ‘fix’ issues that may arise . . .

    Just another viewpoint this morning (-:


  4. Ron Saikowski says:

    Did you add any additives that might not have been available in the 60’s when UC Davis conducted its tests? Color enhancers, tannin enhancers, yeast additives, etc. might have a major impact on submerged caps since those skins were in the juice all of the time. I don’t want to see this concept/discussion. Keep up the great dialogue! …..a Texas want-to-be winemaker

  5. Entertaining blog. My colleagues and I were just talking about this the other night. Also your blog looks nice on my old palm treo. And thats rare. Nice work.

  6. Have you ever considered adding more videos to your blog posts to keep the readers more entertained? I mean I just read through the entire article of yours and it was quite good but since I’m more of a visual learner,I found that to be more helpful well let me know how it turns out. Keep up the great works guys I’ve added you guys to my blogroll. This is a great article thanks for sharing this informative information.. I will visit your blog regularly for some latest post.

  7. I admit, I have not been on this webpage in a long time… however it was another joy to see It is such an important topic and ignored by so many, even professionals. I thank you to help making people more aware of possible issues.Great stuff as usual

  8. Myron Reedy says:

    Keep writing, I simply can’t get enough. You’re doing a standup job, and I thank you for it.

  9. admin says:

    Yes, I use Wordpress, and I have no html experience.

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