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Vessels 101: Stainless Steel
If you’ve ever done a tasting at a winery, chances are someone was telling you about how each bottle was made, and that some spent time in oak, some 100% in stainless steel others maybe in some concrete egg thing. Are these just talking points to fill time or make the person behind the bar sound smart? Nope. It all matters. And below I’m going to explain why with a few of the most common vessels used to ferment and age wine.
Wine can really be fermented and aged in almost anything. But over the years, a few vessels have proved themselves to be most effective because of convenience or what they add to the finished wine. And although these vessels will be discussed separately, in practice winemakers typically blend wine from a few of these vessels to bring certain aspects of each to the finished wine.
The point of this page is to give you an understanding of how each vessel affects wine, so that when presented with this information on a bottle, you will be able to not only understand why they were used, but be able to predict what flavors may be expected in that wine.
So first, let’s take a look at the most common vessels, and how they affect each wine.
Stainless Steel
Why is stainless steel used?
This will be a much shorter section than oak because when it comes to stainless steel, it’s more about what it doesn’t do to the wine.
The main draw to using these tanks is that they are completely inert, that is that they do not impart any flavors into the wine, and instead preserve the natural characteristics of the wine. They can also be sealed so that no oxygen at all gets in, further preserving the natural state of the wine. On top of that, they are easier to clean, regulate temperature, and have a long life span.
These tanks also allow for pump-overs during the fermentation process. This is when a hose is attached to the bottom nozzle, hooked up to a pump, and then brought to the top of the tank to be poured in through an opening at the top.
The reason for this, which is known as “cap management” is to circulate the wine while its fermenting, and to have it pick up as much flavor and color as possible from the skins of the grapes that start to gather at the top. It also helps with introducing a bit of oxygen into the wine so that it doesn’t start to pick up too many reductive qualities.
If you hear a winemaker talking about how the wine has “good extraction,” they are probably talking about the color or concentration of the wine from this pump-over process, or a few other techniques that are discussed in the Aromas & Flavors section.
How are they used?
Stainless steel tanks can be used for both fermentation and aging. In practice, most wine is fermented in stainless steel first to give the winemaker a pure foundation to work with. From there it can be transferred to barrels or other vessels depending on what the winemaker is trying to achieve.
The wine can also just remain in these tanks for the entire aging process if the goal is to showcase the naturel elements of the wine, or maintain freshness.
What type of wine are they good for?
Since the tanks impart no added flavor, they are best suited for wines that a meant to be bright and have lots of fresh fruit flavors. A lot of lighter body reds or crisp, high-acid whites will be fermented and aged in 100% stainless steel so that you get to experience only what the wine naturally offers, without the winemakers influence.
Two terms you may come across while discussing wine are oxidative and reductive. Both have to do with a wines exposure to oxygen during the fermentation and aging process, and each come with very different flavors and aromas.
Oxidative
This means that during the wine making process, the wine was exposed to controlled amounts of oxygen which will add earthier aromas and deepen complexity. The best ways to achieve this are by using oak barrels, stirring the wine, or just not sealing the tanks.
Risk: Wines can get too oxidized and start to lose their flavors or even turn to vinegar, so control is key.
Reductive
In this instance, a winemaker tries to avoid as much contact with oxygen as possible. This allows for the wine to maintain its bright fruit flavors, and a fresh, crisp texture. This is normally done with stainless steel tanks that are topped with inert gas and then sealed shut.
Risk: A wine can start to taste vegetal or pick up notes of sulfur if no oxygen is introduced (think those bags of lettuce in your fridge you promised were to make a salad…).
Solution: In practice, the winemaker will typically use a blend of these techniques depending on the condition of the initial grapes, and the intended final product to balance out the wine.
Also, reductive qualities in a wine can sometimes “blow off” with some aeration either in a decanter or by swirling. An oxidized wine though, is unfortunately toast and should probably be used for cooking.
Conclusion
Stainless steel has become an invaluable asset to winemakers due to its predictability, low cost, and easy maintenance. It allows winemakers to craft wines in their purest forms, and then decide the next steps.
It’s becoming more common to see 100% stainless steel wines, even in massive red wines because of the trend of wanting to taste the wine as an expression of its terroir, rather than combined with any additional flavors.
Click below to explore other vessels.