Here’s an extreme case: Two 750s carefully filled by siphoning from a barrel to be poured as barrel samples at an open house the next day. No contact with the corks, as they’re stood up for the 16 hours. At the open house, one is beautifully expressive, the other so muted it gets pulled. Three hours later, the muted bottle has “opened up” about 90% of the way.
If you pour at events or tasting rooms, you experience variation in young wines from the same case often enough. Sometimes you come across a very anomalous bottle. Sometimes that bottle comes around with time.
I’ve proposed before that since many young wines are cycling through phases - you certainly experience that tasting from the same barrel over time - that two bottles in the same case can be doing this out of sync with each other. In other words, that’s not really bottle variation. Perhaps “bottle mood”.
Of course, young wines can have true bottle variation, too. Wines aren’t likely truly evenly distributed in a tank. There may be some variation on the bottling line. Stuff like that, with the highest degree of quality control.
My guess would be along the lines Clark Smith says about colloidal structure. I’ve read what he said in relation to filtering. I’ve experienced “bottle shock” from filtering. I’ve also tasted side by side, during bottling from a single barrel, a sample drawn from the barrel against a sample from a just bottled bottle. Quite a contrast. Protected from oxygen, not filtered. Just the trauma of going through the bottling line. With filtering, Smith uses the term “bruised colloids”. Point being, the wine is chemically exactly the same. It’s just this loose structure of the same molecules is organized differently enough that the wine doesn’t show the same.
Note that bottle shock isn’t universal. From the same line, same day, some wines may come out shocked while others will taste exactly the same from a just bottled bottle as out of tank.
I’ve opened 5-6 bottles of the same wine from the same pack at the same time for wine tastings and tasted them each to check for corkiness, and frequently found bottle variation. Usually not by much, but sometime large variations occur.
If we accept - as I think we do - that wine changes in the bottle, whether we call it maturing or improving, we must accept that each bottle ‘does its own thing’ once bottled. Each bottle has a different cork, each bottle even in the same pack experiences slightly different storage conditions during transport from the winery through distributer, wholesaler and retailer, and other factors - as noted above - on the bottling line can also affect.
Anyone who uses bark cork is going to have bottle variation. This variation is one of the main reason we are trying to avoid bark cork as much as we can; most of the conversation is about corkiness but random oxidation is much more common.
To eliminate or reduce bottle variations (in my opinion) you would need the following conditions to be met: Sterile filtration prior to bottling (which implies some sort of filtration prior to sterile filtration), synthetic cork or similar closure that is consistent (and TCA free) and consistent storage conditions after bottling. Some would argue that there are alternatives to filtration for stability but I think that would leave the door open to inconsistencies (there is an exception which is a chemical added during bottling that sterilizes the wine without filtration called Valcorin - or something like that). Also, filtration makes the wine consistent; in other words, one bottle doesn’t have crud in it from the bottom of the tank.
In my opinion, these conditions are essential for white wines but red wines are more robust and tolerant of variations as well as not filtering. Moreover, red wines are more often “nutrient deserts” such that microbial activity in the wine is not possible because there is nothing for microbes to eat (e.g., residual sugar, citric acid, malic acid, nitrogen). Also red wines have higher alcohol which helps to protect the wine in some ways.
Unfortunately these things are not very sexy and not promoted in the industry to consumers. For example, usage of synthetic corks is actively discouraged by cork companies. Cork is a natural product and any wine using cork will have variations for better or worse. I would expect larger producers to lean towards consistency to reduce losses/refunds which would explain why larger producers are more successful in reducing bottle variation.
Edit: With regard to the tanks and inconsistency in blends, larger tanks are required for 100% consistency. Large producers will have tanks that are massive (e.g., 100,000gal) to ensure that their blend is consistent. However, there are techniques to make wine consistent in a series of smaller tanks by racking/mixing. The mixing/racking practice is detrimental to the wine quality and I would guess that some producers minimize this which would lead to more inconsistency. Locally in Oregon there are some producers with nation-wide distribution that produce wines like Coca-cola where it tastes the same year after year and they will utilize larger tanks and the less-sexy technology discussed here… also they don’t use wood barrels.
