“The chemistry of wine grapes begins to change the minute they are picked, and transporting the fruit over long distances via truck can have a deleterious effect on the quality of the finished wine.”
Saw this on a winery website. The winery was touting their estate vineyard and then gratuitously inserted this statement as well.
So my query is this: Other than the obvious example that fruit bins being exposed to prolonged sunlight/heat/elements can damage the fruit contained therein, can anyone point to any science that the broad statement - 'the chemistry of wine grapes begins to change" and transportation can have “deleterious effect[s}” is correct? Looking for papers from Davis, Fresno etc. that may deal with this subject.
My guess is this is just overstated, misguided marketing but if anyone can point me to a paper that may substantiate this, I would be most interested and appreciative. Thanks!
From what I’ve read and experienced, two factors are involved. Living fruit is actively defending itself against molds and such. If you pick fruit that’s in good shape there seems to be enough vitality that under reasonable conditions they transport just fine. Fruit on the vine that’s entered senescence is already struggling to protect itself. So, think of citrus for an analogy. A fresh picked young lemon can sit on your counter for a couple weeks at a reasonable temperature. Some lemons can hang on a tree up to 18 months and be protected, but the pith area bloats up and they lose oils in the skin. Pick one of those and leave it on your counter and it’ll be covered in mold in a day or two.
This might help begin to search: senescence - Google Suche
From my experience shipping PN from AV to Sonapa the main thing that happens that can change the final wine is oxidized juice in the bottom of the bin which requires dumping it or a pretty big hit with so2. I have also seen higher levels of VA from fruit picked on the same day one fermented in AV the other trucked for 2-3 hours had much more va on first juice sample. I imagine as you state higher temperatures accelerated the production of VA and likely any other yeast/bacteria along for the ride.
If your not going to include any whole clusters and stems I would also expect to see higher pH in trucked fruit as the juice has some time in contact with the stems. Now if your including them then it won’t matter.
The biggest year I saw different quality fruit trucked vs. not was in '12 when they were repaving the 128 road to Sonapa. Every bridge had a 4-6" 45* bump in the road and no matter how slow you drove some fruit was compressed by nearly half in the bin by the time it reached the winery.
Personaly I would be more interested in night pick chemistry vs early morning pick chemistry. As I have seen some not easily explainable differences in fruit picked 9pm-2am and 6:30 am to 9:30 am the same day.
Full disclosure. At Foursight I only work with fruit grown on site and no trucking is involved. I do believe early morning picks followed immediately by sorting to fermentor and put in winery by 10-11am takes out a lot of variables. The fruit is naturally 40-45* heats up on its own (I don’t heat or cool fermentors white or PN) and I don’t use so2 until malo is done in barrel.
I don’t use temperature control machines at all for fermentation. We use night time ventilation to keep the cellar 58-62 year around and I run that fan 27/7 when fermentors are active to evacuate Co2. I may start cold stabilizing my whites at some point down the road. I use small fermentors, T-bins, depending on how many whole clusters I put in, I can fill them with .7-.85 tons. The whites go to barrel and 55 gal stainless drum. Most vintages were harvesting in 32-38 degree temperatures so the fruit is naturally cold and some would call it a natural cold soak and as you state I don’t force it with refridgeration.
I do not inoculate for yeast or ml. We built a new facility on the property that has never had any packaged yeast or ml on site. I let them come up to temp and fermentation naturally over time. If they need a few hours in the sun I will do that in late/cold years if things are not active after a week or so. 21-28 days on skins then wooden slatted basket pressed at cap fall.
Usually to 70* by day 4-6, peaking 90-95* on day 9-11. Then I get a long tail due to whole cluster berries breaking and releasing sugar. I start with one punchdown a day, then into 70’s-80’s 2 punchdowns, then 3 for upper 80’s into 90’s and the same on the way back down post peak temp.
Also I use guacamole bowls filled with dry ice pelletts that I refresh 2-3 times a day to keep a co2 blanket pre 70* or so and post 70* or so. I use breathable food grade fabric covers to keep fruit flies out and the co2 near the surface of the must.
Joe,
With respect to using the dry ice in the guacamole bowl, why not just pump in co2 from a tank? Is it a timed release kind of thing with the pellets?
Thanks,
Noel
I have tried a lot of things over the years. I like the dry ice in the guacamole bowl so it does not touch and burn the skins. The bowls are a very thick food grade plastic and even when the cap is soft at the end they float on top. Also as you correctly state it is kind of time release, they last 8-12 hours when filled to the brim, as well as the fact that it is very cold and seems to settle over the cap very well. Also I can just pull up a corner of the covers I use and place them in the center. There is not a lot of room if just lifting a corner to get the co2 attachment in there for good full coverage. If I take the lids off and use co2 gas then put them back on there us to much air movement to keep the gas in place.
I have a co2 tank and snow making attachment which I use to purge the T-bins prior to putting the whole clusters in the bottom of the bin. Because the bins are open top just gassing has not worked great for me. I have tried plastic lids and the ones I use now food grade fabric with elastic string around it, like the bottom of a ski jacket, to get a good tight seal so fruit flies don’t get in. Once for a batch of 100% whole cluster home wine I even tried a co2 release timer meant for grow rooms to emit 2 minutes of co2 every 15 minutes and still got way to much VA. I had a plastic lid and the bin was only 60% full but there still was just to much o2 able to get/mix its way in. The plastic lids don’t seal well enough to keep fruit flies out. Fruit flies + time + o2 = to much va for me.
Temperature of the fruit is not as cold in night pick vs. day pick. Though it seems temperature in fermentor can be cooler if the fruit has to travel 2-3 hours and then be processed. Night picks have crews waiting to process the fruit at 6-7am.
I have also seen higher pH and lower TA on night pick vs morning pick. The brix are a little higher as well. Now the differences are small and could just be some error in sampling or testing equipment. Though I have seen trends in 3 vintages now. Same clone, vineyard, pick crew etc. just different night vs day picking time and adjacent rows in the same block. I assume the brix goes up thru the day and then goes back a little at night. I assume the pH and TA do the same and night pick does not give the fruit enough time to cool off and recover. The additional heat the night pick grapes retain definitely makes fragile PN skins more prone to bursting and de-juicing so some of the pH/TA differences may be due to juice in contact with skins/stems/o2. Where as cold morning picked fruit processed as fast as its picked on site keeps many more skins intact and temperatures to bin much cooler.
Being that I am really trying to dial in the picks so that no water (never ever) or tartaric acid (once in a while here or there <10% of my lots) is needed these small differences matter a great deal to me. Nitrogen does not seem to change and its not an additive I’ve ever used either. It must me more stable than the sugars and acids. Also I do my berry sampling in the early morning to that when I am tracking it for a early morning pick. I make the pick calls 4-5 days out to assure a crew. Up here I am battling the sparkling guys for crews as I am the first to pick still wine grapes in AV every vintage at Foursight, 9 years running.
In a similar vein, I’ve been wondering about +/-'s of crushing/destemming or pressing at/near the vineyard and then trucking the must (kept cold, of course), rather than the grapes–anybody have any insight on this?
There are 2 producers up here I know that do that. They seem to be happy with it. If available I would choose that over trucking. The folks I know that do it use bonner bins and a fair amount of whole clusters. I just don’t think it will be easy set up a clean winery environment in most vineyards.
They ferment in the bonner bins. They like to be able to fit 1 ton of fruit with whole clusters into the bin. The lids for the bonner bins seal way better than anything I have seen of T-Bins which is what I ferment in. Im talking about PN so I think the goal is whole berries with some whole clusters in the bottom of the bin. I don’t think a flex tank could accomplish that.
The flex tanks I have only have a 1.5" tri clover fittings. To pump must in our out I think you would need 3". I guess if you could pump it in from the top then you could put a hose in thru the top and pump it out. The folks I know that do this as well as I don’t have must pumps and de-stem directly into the bin on top of the whole clusters. The de-stemmer is on legs big enough to put the bin directly under it.