Whole cluster vs carbonic

Hope this isn’t too much of an amateur-ish question, but:
If the only difference between these two styles of fermentation is the amount of oxygen involved, what accounts for the drastically different profiles? Two examples:

Raen pinot: 100% whole cluster. Tastes like twigs and has noticeably more tannin than most Cali Pinot. When I made this observation the rep told me “yeah because of all the stems”.
Beaujolais village: all fruit flavors with minimal wood notes or tannin. But it also has “all the stems”.

I’m just using these two examples as they’re recent experiences of mine, but in general I always find wines marketed as whole cluster fermented to be green/wood-y, and carbonic wines aren’t. So what accounts for the difference in flavors here?

I believe a wine could be both. You could destem and use carbonic maceration or you could use carbonic on whole cluster. The coolest place to compare the differences is in Beaujolais where there are a variety of practices.

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Strict carbonic maceration was invented in the Languedoc in the Post War period as a way of taming the tannins of Carignan, Grenache etc. (The technique of délestage, i.e. rack-and-return, was also popularized around the same time for the same reason). Strict carbonic involves fermenting whole, uncrushed berries in a closed tank with the valve at the bottom open so any juice accumulation from ruptured fruit is drained out of the tank. Thus juice-to-skin extraction, from maceration in the conventional sense of the term, is as far as possible eliminated. Even with the most gentle destemming this technique, in its strictest sense, is impossible to realize with destemmed berries, as too much juice will be liberated.

Whole-cluster fermentation is a much broader category, including carbonic maceration, but also including making wine with fruit that is fully or partially crushed but not destemmed, as at for example Rayas and Domaine de la Romanée-Conti.


This is what I’ve understood. Destemming is incompatible with carbonic.

Whole-bunch is the umbrella term, which includes both carbonic and conventional fermentation. It just refers to grapes not being destemmed, but they can be crushed.

Carbonic is wine made with whole, uncrushed bunches in a vat filled with CO2. Semi-carbonic is a combination of carbonic and conventional: some of the bunches are crushed (either by getting crushed under the weight of the other bunches, or by purposefully crushing them). Once the fermentation starts, it fills the fermentor with CO2, triggering carbonic fermentation in the uncrushed fruit.


Carbonic fermentation takes place mostly or entirely without oxygen inside grapes that are left uncrushed (with or without their stems). That yields different fermentation byproducts – and particularly fruity elements.

By contrast, most wines made with stems undergo (at least mostly) conventional fermentation, open to the air (oxygen). But the stems are left in during the maceration and fermentation.

If you’re getting twiggy/woody notes, that might be because the stems weren’t ripe enough or the winemaker wasn’t experienced enough with stems. (Of course, there could be other reasons.). There’s an art to gauging stem ripeness, and when and where, and in what amount, to include them. But, done right, stems can (counterintuitively) actually soften the texture of a wine and add complexity. They can affect tannins and acids and alcohol conversion rates.

This is a terrific article by Jamie Goode on stem inclusion, including the fact that, if you ferment with full clusters, you’re likely getting some carbonic fermentation.

Gamay in Beaujolais can yield wines with tannins, but I don’t believe more serious Beaujolais bottlings rely much on carbonic maceration. That tends to be reserved for the simpler, early-drinking bottlings.

Carbonic maceration - Wikipedia.


The winery where I worked never used a crusher. Destemming liberates a lot of juice especially for the thin skinned varieties. The 100% whole cluster lots were foot stomped. The carbonic lots we carefully loaded good looking clusters into a small tank and added dry ice.



There are many factors at play as to some wines that are fermented with whole clusters show ‘stemmy’ characteristics while others don’t. I have been fermenting all of my reds using 100% whole clusters for a decade now, foot stomping on day 1 to release enough juice and breaking enough berries to allow me to do ‘traditional punch downs’ starting on day 2 and allowing earlier integration of the juice and stems.

To me, there are three key factors when it comes to minimizing ‘stemminess’ in these wines - 1) keeping fermentation temperatures in a ‘moderate’ level and not allowing them to get too high; 2) making sure that alcohol levels are not too high as alcohol is a solvent and will pull out more qualities from the stems the higher the alcohol level is;; 3) time - some wines need more time in oak to allow for integration

I have also been doing a carbonic maceration wine for the past 4 years - the grapes are hand loaded into a tank whole cluster and as uncrushed as possible, the tank is hit with CO2, and then closed up and literally left alone for 3 weeks. The tank is then drained, and the intact whole clusters, which have partially fermented, are loaded into the press and pressed, with the subsequent juice/wine placed in a stainless tank to finish fermenting off its skins.

Hope that helps.



And indeed, I never pick up any aggressive stemmy notes in your wines, even when they are young.

What kinds of flavors, aromas, tannins etc. do you think that the whole cluster add to your wines, as compared to if you made the wines the same but destemmed?

Great question - and the answer is . . . It depends upon the variety and the vintage.

I will say that the stems add bitter compounds, increased but not obtrusive tannins, and add ‘non fruit’ aromatics the the wines - from herbaceous elements to spice elements like peppercorns and tea leaves.

In general, I say that the stems make my wines more like old vinyl albums - scratches, imperfections - that add a warmth and character to the wines that they would be missing without.

I should also note that I am using 4+ year old oak barrels so the tannins from the stems are helping give structure too.

Hope that helps . . .



Foillard, Desvignes, Lapierre, Metras, and others use semi-carbonic maceration; I’m pretty sure that includes the special cuvees (Lapierre Cuvee Marcel; Desvignes Les Impenitents; Metras L’Ultime; Foillard 3.14) that are meant to age longer.

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So, CM is an enzymatic conversion that occurs in an anaerobic environment at a much slower rate than yeast fermentation. There are many variations in process. Grape variety, vintage, style preference/goals, equipment constraints… CM does not do much in the way of alcoholic conversion, usually 3 or 4 brix at the most (I’ve seen the rare claim that someone gets a lot more, but am skeptical). It’s mostly about creating new compounds, mostly precursor compounds in that the yeast will then convert those new compounds into others compounds by the time fermentation is complete.

One common hybrid variation is picking out the percentage pristine clusters you desire and placing them on the bottom of a fermenter, then covering with pressed juice. Ferment til the juice is dry, then press. The unbroken will release their sugar, so the fermentation will continue in the new vessel.

An unmentioned factor with stems is they raise the pH of the must, which, depending on other factors can guide your methodology.

We did 100% carbonic on some wines, the hybrid partial whole cluster method above on quite a few, 100% stem inclusion with minimal to moderate stomping on others. Our Mission was a blend of two ferments: Half done with CM pressed at about 2 weeks and finished in stainless, and half with 100% stems and gently stomped to get enough juice to cover the berries.


What, if anything, is the connection or degree of overlap between carbonic winemaking and reds with spritz?

I really dislike red wines with any fizz, and I equally dislike the way those wines taste if/when the fizz goes away from shaking, decanting, waiting, whatever.

But I’m not sure if that has some partial correlation to carbonic winemaking or none.

Little or no correlation and I share your dislike of significant dissolved oxygen where it wasn’t intended. Tends to be either refermentation after bottling, which generates off fermentation odors, or wines produced in cold cellar without racking (as sometimes with Pinot).



If a red is fermented and/or aged in stainless, it may indeed have a higher level of dissolved oxygen. That is true of both carbonic and non-carbonic wines . . .



Note that the carbonic wines do most of their fermentation after the carbonic has stalled and the grapes are pressed, hence Larry’s comment that completing fermentation or aging in stainless affects both carbonic and non-carbonic wines.


Great post Larry. This last part is an important one to highlight for the OP I think. One of the reasons that some carbonic wines are so light on their feet is exactly this: that most of the fermentation happens off the skins and stems. Because the alcohol content is so low at the point of pressing, you get a wine with very little in the way of color extraction, astringency, or stemmy character. This is particularly convenient if you are making carbonic wines from very low-ripeness fruit, for which leaving the must in contact with the stems during the later stages of fermentation would impart an overt stemmy character. It also helps keep bitterness low because the seeds are no longer present late in the fermentation, which is when bitter compounds are most strongly extracted from the seeds (and which can be very potent in low-ripeness grapes)

But yeah, there are so many ways of making wines whole cluster, and several ways to get different amounts of carbonic character in a wine. Because carbonic maceration can happen in any unbroken grapes in a carbon dioxide atmosphere, it is common to some extent in whole cluster wines that experience little physical maceration early in the ferment.


Most wines will have some of both. But you don’t have to have stems in a carbonic ferment. Carbonic is a CO2 saturated ferment, you’re saturating the tank for ferment with carbon dioxide from the first stages of ferment.

Whole cluster generally will have some amount of carbonic influence because some percentage of berries don’t rupture until the ferment is allready rolling and the juice from them is fermenting carbonically. Of note, I find more carbonic influence in ferments with 25-40% stems than I do in higher whole cluster ferments. Thats because there is better early juicing in the destemmed portion of the fruit that layers over the percentage of stems with juice released by destemming.

Our ferments are quite a bit less influenced by carbonic fermentation now that the amount of stems is higher. If you are drinking now, more carbonic may be your preference, but for long term aging I prefer less carbonic influence.


Thanks everyone, and Larry, Wes and Marcus, in particular.

(I hadn’t seen William and Otto’s posts when I sent my earlier post. I guess we were composing at the same time.)

There is also stem inclusion, where berries are destemmed and then the stems are chucked into must. My feeling is that the whole cluster fermentation and stem inclusion are very similar. The reality is that due to the weight of the berries, only a very thin layer perhaps at the very top experience the intra-berry whole fermentation - most are crushed by their own weight and behave exactly like they’re destemmed with stems included.

Stem inclusion has the extra benefit that it’s easier to punch down. Whole clusters are painful to punch down and can as a result of that get more exposure to air in an open top fermenter, potentially developing higher VA.

BTW, I did stem inclusion with one of my Zinfandels last year and I have to say, I don’t know why everyone isn’t doing this! I’s tasting absolutely amazing right now (maybe it will change).

But historically, there seems to have been some resistance to whole cluster/stem inclusion on particularly Zin. Baffling. On paper, it looks to be the absolutely best suited grape for it - thin skinned, low in tannins. Seems like the ideal candidate for a little bit of tannic beef-up and greener notes to fight the fruit off. And so far the issues from others confirm this: I’ve had Patrick Cappiello’s Monte Rio Zin done this way and it was a cut above most other. Stellar.

I’ve understood that this is completely the opposite. I’ve heard many winemakers say how they are surprised finding whole berries even after a crush. The bunches - especially the tight ones - retain their shape surprisingly well, protecting the grapes from breaking. After all, they don’t break up immediately after applying some pressure, but they deform, ie. get squished yet don’t break. When the weight is applied evenly to all the grapes, the pressure doesn’t actually become that big per one grape, even if there is tons of fruit on top of them.

And, naturally, the wider the fermentor, the less pressure there is.

Best suited? Carbonic maceration was invented to combat the high tannins and high acidity of Carignan sourced from high-yielding vineyards. With carbonic maceration you don’t get much extraction from tannins and up to half of the malic acid is converted to alcohol via malate degradation. If you have a variety that can be already rather low in acidity, I guess you don’t want to lose what little you have left with the loss of acidity that comes from a) carbonic maceration; b) potassium from the stems.