Whole Grape Fermentation

[crushday]

I’m wondering if anyone has experience with whole grape fermentation. Last week I bought a drum of Syrah from Peter Brehm. During thawing, I removed the lid and was surprised to see many of the grapes whole and not crushed. After it was thawed I progressed like I normally would. I added EX-V during the thaw and maceration and pitched Avante yeast.

Today, I’m two days into the fermentation. Only the top couple inches are loose and form a punchable cap but the rest is very compacted. The loose top is only that way as I’ve been pounding the grapes down with my cap punching tool in an effort to crush the grapes.

What do I do? Most of my web searching leads me to intracellular fermentation. On the grape description from the Brehm website, it says this: “Our destemmer allows many berries to pass unbroken.”

Must temp readings are 70 and a cap does form albeit a shallow one.

Here’s a pic of the must that was taken during thawing…

 

[BarrelMonkey]

I work at a winery and we use a destemmer that doesn't really crush the grapes - a lot of the time they are like little solid marbles, just as you describe. You're right, the cap is pretty hard to punch down for the first few days (we stir it around as best we can) and it's also hard to take samples for brix measurement. Once fermentation takes off the grapes will start to break down and it will get easier.

 

[crushday]

@BarrelMonkey - this is extremely helpful. I'll stay the course...

Without giving away trade secrets, can you help me understand any appreciable benefits to whole grape (cluster) fermentation? I've heard of several wineries in the Willamette valley performing this function on cold weather Pinot Noir and only recently made aware that Syrah is a good candidate.

I appreciate your time.

 

[mainshipfred]

Whole cluster has always been deceiving to me. I've read it a few different ways. One is the grapes are crushed and destemmed but then both the grapes and stems are fermented together. The other is what I would call truly whole cluster. This is where the clusters are simply put in as they were picked. Then there is carbonic maceration which is again different. But more directed to your question, and this is only my opinion, once the grapes are removed from the stem there is enough of an opening for the yeast to enter and start the fermentation.

 

[Johnd]

I’ve only done one mostly whole berry ferments. If yours is similar to mine, you may find that after pressing, your SG will rise slightly, as some of the juice inside the berries is released, and not as far along as the free juice is. Leave space in your carboys in case this occurs, as your fermentation may be a bit more vigorous than you’ve previously experienced. I had some near overflows before I realized what was happening and pulled some juice out of each carboy to provide some head space. Other than that and PIA punching, it was much the same.

 

[crushday]

"...there is enough of an opening for the yeast to enter and start the fermentation."

Thanks Fred! This has been a head scratcher for me, lol... After I knew it was thawed, I was surprised at the grapes' resistance to my stirring spoon!

 

[crushday]

I’ve only done one mostly whole berry ferments. If yours is similar to mine, you may find that after pressing, your SG will rise slightly, as some of the juice inside the berries is released, and not as far along as the free juice is. Leave space in your carboys in case this occurs, as your fermentation may be a bit more vigorous than you’ve previously experienced. I had some near overflows before I realized what was happening and pulled some juice out of each carboy to provide some head space. Other than that and PIA punching, it was much the same.

Very helpful, John. I've been trying to ascertain RS after press. I suspect this ferment is going to take a bit longer than normal. I'm hoping for a full, inky Syrah that I'm planning to keep mostly 100% varietal. I also have a Carignan fermenting that I'm planning on blending with some of this Syrah.

Thanks for the help!

 

[BarrelMonkey]

Without giving away trade secrets, can you help me understand any appreciable benefits to whole grape (cluster) fermentation?

Disclaimer - I'm not an experienced winemaker! - I've been working in the cellar for a few years as a way to learn more about wine making, and I'm hoping to do my first solo winemaking this year. But my understanding is that you get some additional flavor components from whole cluster fermentation. It's not true carbonic maceration (which uses a layer of CO2 to force anaerobic conditions), but there are similarities and you do get different chemistry going on within the grapes. There's potential for extracting flavor/structure components from the stems as well, though I think you have to be careful not to have too much green stem material which can promote odd vegetal flavors. This article might be worth reading for more details.

 

[NorCal]

I’ve always set my crusher at the most outward setting, with rubber gears. A lot of whole berries get through. I think it tends to extend fermentation, which I’m looking for. I tend to do firm press downs to make sure I assist the process of releasing the sugars. I also found that during press, some berries that made it through the whole process will give up some sugar, this RS is consumed by the wanting yeast after press.

 

[sjjan]

All I know is that some skip the destemming and do whole cluster/grapes pressing. But whole grape fermenting is something I am not aware of.

 

[Ajmassa]

I just experimented with this last fall. I took about 30% of the grapes (full clusters still on the stems) and tossed them in the fermenter. Then added the rest of the crush on top. A poor mans carbonic maceration. So not exactly the same as just having a higher than normal % of whole berries- but same principals involved.

I read a good bit on it. There’s a TON of literature out there. And literally everything is a variable that has some affect on the final product.

But in the end they say that the oxygen free intercellular fermenting helps soften the tannin, acid, and color. (A portion of the juice is fermenting w/o skins contact inside the berries- so it makes sense) Supposed to bring out the fruitiness and drink younger.

Though if you use enzymes or have a long ferment then probably will bypass any whole berry affects I bet. Which isn’t a bad thing your this case.

*Side note— I noticed even after fermentation with vigorous punch downs, and a hard pressing — within the press cake there was still a good amount of whole berries intact. Ended up fluffing the cake and smashing it up with a 2x4 as best I could.

 

[sjjan]

I just experimented with this last fall. I took about 30% of the grapes (full clusters still on the stems) and tossed them in the fermenter. Then added the rest of the crush on top. A poor mans carbonic maceration. So not exactly the same as just having a higher than normal % of whole berries- but same principals involved.

I read a good bit on it. There’s a TON of literature out there. And literally everything is a variable that has some affect on the final product.

But in the end they say that the oxygen free intercellular fermenting helps soften the tannin, acid, and color. (A portion of the juice is fermenting w/o skins contact inside the berries- so it makes sense) Supposed to bring out the fruitiness and drink younger.

Though if you use enzymes or have a long ferment then probably will bypass any whole berry affects I bet. Which isn’t a bad thing your this case.

*Side note— I noticed even after fermentation with vigorous punch downs, and a hard pressing — within the press cake there was still a good amount of whole berries intact. Ended up fluffing the cake and smashing it up with a 2x4 as best I could.

Interesting!

 

[user 38734]

Mr.Massa is correct, there is a lot of information about whole berry fermentation on the internet. However, whole berry and whole cluster fermentations are completely different stylistic techniques.

Personally, I will never again crush my reds (ex Rose’).

 

[Ajmassa]

Mr.Massa is correct, there is a lot of information about whole berry fermentation on the internet. However, whole berry and whole cluster fermentations are completely different stylistic techniques.

Personally, I will never again crush my reds (ex Rose’).

I was under the impression whole berries off the stem would have the same principals involved as whole cluster , but just to a much lesser extent and quicker to shift to regular fermenting since there’s an opening on the berries. Is that not correct? Was simply trying to relate @crushday ’s grapes to what I learned last year.

I know it’s difficult to even attempt to get into the particulars since there’s so much information involved. That’s why I mentioned the literature out there.

Also @Booty Juice , no more crushing? Bold statement. Care to elaborate?

 

[BarrelMonkey]

I was under the impression whole berries off the stem would have the same principals involved as whole cluster , but just to a much lesser extent and quicker to shift to regular fermenting since there’s an opening on the berries. Is that not correct?

I think that's right - as you say, the grapes are not 'sealed' in whole destemmed berries as they are in whole cluster berries, so much less of an effect.
The first wine I made (or I should say participated in making - my neighbor was the winemaker) had about 10-15% whole cluster, which she left in for 'more complexity'. The rest were destemmed and crushed. When fermentation was done and we pressed the grapes, I tasted one of the whole cluster grapes and compared it to one of the destemmed/crushed grapes in the same bin. They were strikingly different, and although I don't recall enough to accurately describe the difference I think the whole cluster grapes have a sort of 'fruit candy' character. I find this distracting if overdone, and although it's dangerous to generalize I am leery of wines that have very high (50%) whole cluster content.

 

[user 38734]

AJ,

I can tell you my experience, but can’t explain the science behind it (if there even is any).

WHOLE CLUSTER FERMENTATION: The purpose is to add tannins and other flavor elements that the stems impart. Some of my relatives in Southern Italy will add 10% to 25% whole clusters, while my relatives in Northern Italy and Slovenia may add 50% or more. The difference is due to the woodiness (preferred) or greenness (not preferred) of the stems; the cooler northern climates produce a more woody stem at harvest time, so they’ll go with higher percentage whole-cluster ferments. From US commercial winemakers I know - Here in San Luis Obispo there is a high-end commercial PN winemaker (CD Drew evidently likes his wines and I occasionally use his fruit) who uses a small percentage of whole clusters in some of his ferments. In the Willamette Valley (Oregon), a much higher percentage is used. Green vs woody.

WHOLE BERRY FERMENTATION: The purpose is a slower fermentation, much of which will occur inside the berry, accentuating the fruit, minimizing tannins and producing a smoother wine.

Within the high end wineries that I have some knowledge of, the best-practices are whole berry fermentations. Universally. I can’t think of a single one that doesn’t whole berry ferment. Either using a meticulous hand sort, or an optical sorter (which can be purchased or rented). To take this another step further; whole berries which are gravity fed (conveyor belt) vs pumped (where breakage can occur) into the fermentation vessel.

I don’t harvest and ferment using macro bins. I source fruit from multiple vineyards, usually 4 to 6 different harvest days per season of 250lbs each harvest. So two of us can meticulously hand sort that much fruit in a reasonable amount of time for a (gravity fed lol) whole berry fermentation. The results are pretty striking if you like a certain style of wine. Generic, formula, Parker-style reds are not my preference. Different strokes. I’ll never crush reds again.

 

[AaronSC]

AJ,

I can tell you my experience, but can’t explain the science behind it (if there even is any).

WHOLE CLUSTER FERMENTATION: The purpose is to add tannins and other flavor elements that the stems impart. Some of my relatives in Southern Italy will add 10% to 25% whole clusters, while my relatives in Northern Italy and Slovenia may add 50% or more. The difference is due to the woodiness (preferred) or greenness (not preferred) of the stems; the cooler northern climates produce a more woody stem at harvest time, so they’ll go with higher percentage whole-cluster ferments. From US commercial winemakers I know - Here in San Luis Obispo there is a high-end commercial PN winemaker (CD Drew evidently likes his wines and I occasionally use his fruit) who uses a small percentage of whole clusters in some of his ferments. In the Willamette Valley (Oregon), a much higher percentage is used. Green vs woody.

WHOLE BERRY FERMENTATION: The purpose is a slower fermentation, much of which will occur inside the berry, accentuating the fruit, minimizing tannins and producing a smoother wine.

Within the high end wineries that I have some knowledge of, the best-practices are whole berry fermentations. Universally. I can’t think of a single one that doesn’t whole berry ferment. Either using a meticulous hand sort, or an optical sorter (which can be purchased or rented). To take this another step further; whole berries which are gravity fed (conveyor belt) vs pumped (where breakage can occur) into the fermentation vessel.

I don’t harvest and ferment using macro bins. I source fruit from multiple vineyards, usually 4 to 6 different harvest days per season of 250lbs each harvest. So two of us can meticulously hand sort that much fruit in a reasonable amount of time for a (gravity fed lol) whole berry fermentation. The results are pretty striking if you like a certain style of wine. Generic, formula, Parker-style reds are not my preference. Different strokes. I’ll never crush reds again.

Just to make this clear for me: in the first case you are crushing (stomping) the grapes in the vat but leaving in the stems, etc. In the seconds case you are stripping the berries from the bunch by hand and fermenting them whole, like carbonic maceration? Is this correct?

Thanks,

-Aaron

 

[user 38734]

Just to make this clear for me: in the first case you are crushing (stomping) the grapes in the vat but leaving in the stems, etc. In the seconds case you are stripping the berries from the bunch by hand and fermenting them whole, like carbonic maceration? Is this correct?

Thanks,

-Aaron

Hey Aaron,

REGARDING WHOLE CLUSTERS: My family overseas will destem and crush, then add whole clusters to open top fermenters and punch down. Just like you do except with some whole clusters added in the vessel. The commercial winemakers I know do the same thing except with pump overs. Partial whole cluster, open top fermentation.

REGARDING WHOLE BERRY: Whole berries are placed in open top containers and fermented with punch downs (home gamers) or pump overs (pros). No different than what you do now, except with whole berries instead of crushed fruit.

Native or commercial yeast.

No stomping or carbonic maceration.

Whole berry fermentation is obviously not an option for home gamers who process a lot of quality fruit in one shot, nor do I see the point of doing it with sub optimal fruit. But for someone who sources quality fruit in small batches, it can be a way to ferment the same way as the top end makers, and potentially better than the mid tier guys (ex glycol tanks lol).

A 250 lb harvest, easily hand destemmed by at least two people, yields me 4+ cases of wine. Do that 4 to 6 times per season and you need 200 to 300 corks. Good god, even for my extended family that’s a lot of wine.

 

[crushday]

Just a quick update: I started this fermentation on June 26th by pitching yeast. Today, it’s still forming a strong cap. I’ve been able to keep the ferment in the low 70’s for the internal temperature of the must. I’m in no super hurry for this to complete and only mildly nervous about the length of time for the primary fermentation. Because of the strong forming cap, I’m not inclined to get my hydrometer out.

Can anyone site some benefits or liabilities of a long ferment?

 

[Snafflebit]

I think that whole cluster fermentation is performed on fresh grapes. I did not see this detail mentioned in the thread. Intercellular fermentation is the grape cells themselves metabolizing their intercellular sucrose in an oxygen-free environment. If the fermentation is caused by yeast infiltrating the berry, that is simply old-fashioned fermentation. @crushday I assume your grapes were delivered frozen which kills the berry.

Plant cells produce ethanol as the end product of anaerobic glycolysis, animal cells produce lactate. Acutally both animal and plant cells will produce both end products anaerobically, but this is the preferential pathways. It will not take much ethanol ~5% to build up in the grape tissue to kill the grape berry, but in the meantime esters form interesting flavors in the berry such as what is found in beaujolais nouveau.