The Role of Tannins in the Winemaking Process

I am going to begin this section on home winemaking with asking, what is tannin? Do you know what it is or what it comes from? If you know these things you can begin to understand and how it works in your wine and how it can work into your winemaking repertoire.

For those of you out there who do not understand what tannin is, I am going to start with the dictionary definition:

Tannin — a yellowish or brownish bitter-tasting organic substance present in some galls, barks, and other plant tissues, consisting of derivatives of gallic acid.

From that definition, you might have gathered that tannin does not just exist in wine. It exists in many plants. In more familiar terms, it exists in coffee, tea, bananas, unripe avocados you perhaps tried making guacamole out of too soon. It is that dryness you get if you had a sip of tea before you added some sugar or lemon to it.

In wine, most of us recognize tannin from wine, especially if we have had any experiences in which it made our mouths feel like leather. It is no coincidence then that tannins are the exact base they use to cure leather.

How Tannins Affect Your Wine

Now we know where it comes from and what it is. From this point on we can discuss how tannin will have an effect on the result of your wine and how it takes part in the winemaking process.

In wine, tannin can be derived from a few different things; grape skins, seed, stems and oak. We are going to break them down. The tannins from the grape skins are only, at least in the newer world, going to be used for red wines. In the first beginnings of more refined winemaking in the region of Georgia and even still today, you can find white wines with presence of tannin.

The reason for this is they allow the juice to ferment with the skins, well, actually as whole bunches. So for this type of white wine, referred to as “orange wine,” you will perceive significant tannin.

With the exception to that of Georgia and a very small few of other countries, the only wine we relate to is red wine. Because we ferment the juice while it is in contact with its skins and sometimes even stems.

For lighter varietals such as Pinot Noir, it does not hurt to ferment with whole bunches, as the stems add a sort of savory aspect to the wine and give it more of a backbone. As for tannin from seeds, these are not tannins you want. If you are sourcing grapes for winemaking and you find that the seeds are especially tart and bitter as you taste your wine throughout filtration, you can use a sieve to remove some of them. Of course, removing all of them would be impossible, but if you get too much tannin from the seeds, your wine could be a bit over-the-top in tannins.

How to Impart Tannin Into Your Wine

It is a crucial time during fermentation to impart fruit tannin into one’s wine. It is not complicated, but this comes from careful attention to punch downs if you are using grapes. The grape skins will float to the top of the juice within the first 24 hours following crush.

From the point you add the first food add to the end of the fermentation, you must make sure that these skins are imparted into the juice. You can do this by utilizing a special plastic spoon most winemaking suppliers have for smaller batches and for larger, there is a food-grade tool that basically has a long handle with a large flat plate on the end of it with holes to push into the ‘cap’ (surface of grapes floating on top of the juice) so as to mix your wine, thus integrating tannin.

Additionally, punch-downs are not just for integrating tannin, but they also help impart color and other compounds that are important to aroma, texture and keep the fermentation even and balanced throughout the process.

Balancing Tannins with Oak

Now that we have covered fruit tannin, the following question is to figure out how we can balance those tannins with oak. If you can afford a small or standard size barrel for your wine, then that is great! Use it!

However, not a lot of us have access to getting one or afford one for that matter. There are other options. For modern home winemaking there are some options you can get from many home winemaking suppliers. Most winemaking ingredient kits will have everything you need to impart the right tannin and right amount into the style of wine you desire; from chips to powdered oak to even liquid tannin. Each kit comes with specific instruction for each.

More About Winemaking:

• Tips for Fermenting Wine
• 4 Types of Preservatives in Wine
• Why Sanitation is Important When Making Your Own Wine
• Winemaking Preparation: Do You Have Everything You Need?