It’s Time to Polish Your Wine: Clear, Correct and Combine!

What makes a great wine? One you like drinking, of course. But, it’s not just the flavors in the wine, a great wine draws you wholly into the wine, tasting all its elements in balance. These elements are called texture, the sum of the wine’s parts. Texture includes acid and tannin. A wine with good texture doesn’t create a circus in your mouth. It doesn’t shout out one element such as oak or acidity. If you find yourself noticing an individual element on the palate, then the wine is probably not in complete balance. It’s like someone talking to you while you’re watching a movie, it brings you out of the experience and distracts from the pleasure.

Texture begins at harvest. At harvest a winemaker is a scientist measuring and adjusting the various elements of must or juice, such as the sugar and acid in the grapes. Major adjustments in the wine’s sugar and acid levels should be done before fermentation to allow these changes to properly integrate. Sugar, and thus alcohol levels, need to be spot-on before primary fermentation. But acid and tannin levels will vary with fermentation.

Post-fermentation, small changes can be made to these most important aspects of texture. The winemaker then becomes an artist who paints with these textures, bringing acid and tannin levels into better balance. This can be done by clearing the wine of hazes, correcting texture levels and possibly blending for balance and for extra character. Remarkably, these small adjustments can make a good wine into an award winning wine. They may also be the difference between a silver and a gold medal wine.

Clear the Wine

Although appearance is not technically a “texture,” on the palate, we first taste a wine with our eyes, especially white and rosé wines. Most wine will clear itself after fermentation if given enough time. But complete clarity may take a very long time. Wine contains charged particles (ions) that may make a wine appear clear in its youth, but can form longer chains over time and cause hazes. Changes in temperature can affect wine and cause a clear wine to become cloudy. It’s important that the wine not only be clear in the carboy, but also in the bottle a year or so later.

Filtering alone may not get the job done as ions can be smaller than the filter opening. Fining is usually done first and may do the job completely. Fining agents are usually used in pairs with one attracting positive charged ions and the second, following, application an agent with an opposite charge.

Sparkolloid is a great one-application (and vegan) alternative. It combines a Bentonite-like diatomaceous earth compound with a seaweed companion to clear both charged ions. It is relatively gentle on color and aroma. A downside is that it has to be boiled and applied hot.

Correct For Hardness

Hardness is a term to describe a wine which is not in balance and thus is “hard” to enjoy. There are varying degrees of hardness and can refer to any of the elements of texture, solely, or in combination. For instance high acid levels with high tannin levels in a red wine create a war zone in the mouth. Or where oak, a subset of tannin, can be too forward, drawing the mouth and cloaking the fruit. Acid levels can create hardness, such as a flabby white wine which is too low in acid or a too vibrant wine which is too high in acid. Any of these problems make a wine unpleasant to drink, but some small adjustments may bring it into balance.

Also consider that polishing means small adjustments. Thus post-fermentation adjustments are “tweaks.” These can possibly only make a harsh wine more drinkable, a good wine a bit more appealing and maybe push a very good wine into the excellent category.

Acid Correction

The Northeast and the West Coast of the United States both make excellent wines, but suffer from opposite problems when it comes to acid levels. The west Coast growers would love to have the acid that makes Riesling and other aromatic whites of the Northeast so enjoyable. In turn, the Northeast growers would like their reds to have more sugar and less acid. Opposite problems, but both are a challenge.

Low acidity can be corrected with the addition of tartaric acid before and after fermentation. Acid additions are more stable if corrected before fermentation. There are ways to adjust acid levels after fermentation. To increase acid levels, tartaric acid can be added. Always use tartaric acid and not an acid blend. Though it sounds appealing to have a variety of acids, other acids may react in an unpleasant way with your wine. To measure the amount, bench trials are necessary. Make a 10% solution of tartaric acid by adding 10 grams of acid to 100 ml of neutral water. That is a 10% solution. That adds 1gm/liter to the wine per 1ml of solution. If you find that amount awkward, halve to a 5% solution. Remember that you can also use drops of solution as a measure. There are 20 drops in a ml. of solution. To determine dosage in the finished wine, remember there are 3.8 liters in a gallon.

Reducing acid after fermentation is also possible and there are many options. A gentle method is to induce a malolactic fermentation where appropriate. This process uses malolactic bacteria to convert the malic acid to lactic acid, a softer acid. Once induced, either at primary fermentation or after, you need to test for completion of the process to avoid fizzy wine in the bottle. The reduction amount is dependent on the amount of malic acid in the wine.

A second gentle method is to cold stabilize the wine. At 40F, or lower, some of the tartaric acid with fall out of solution. The colder the temperature, the quicker the process. This is usually a minor correction to the TA and PH. But it may be all that your wine requires.

For a more substantial reduction of acid, potassium bicarbonate (K2CO3) can be used post fermentation. Calcium carbonate (CaCO3) should not be used as it takes a long time to precipitate out of the wine. Also, calcium carbonate may leave a residual taste after fermentation is completed. For potassium bicarbonate use 1gm/liter of bicarbonate to reduce TA 1 gm/liter. Do not dissolve in water, but in a small amount of your wine. I like to work with PH at this point, checking the taste and final PH after separate very small additions. It’s wise to break up the particular wine into liters so that the process is more like a bench trial. The wine must then be cold stabilized to remove the resulting potassium bitartrate solids, which lowers the acid still further. Go, slow!

Tannin Correction

Tannins are crucial in winemaking, not only for flavor but also for color retention and preservation. Tannins will grab oxygen molecules which act as a preservative. Tannin also forms chains linking color molecules called anthocyanins. Tannin gives structure to your wine, supporting the fruit and giving the wine character. Tannin is a big deal.   

Oak will add to tannin levels and will add a spicy flavor. Adding oak to the wine may give more mouthfeel and texture to the wine. If appropriate to the type of wine, it may be a way to make your wine vibrant. There are many ways to accomplish this besides a barrel. Chips are a quick solution but care must be taken to not create a smoky bomb. Cubes or beans have a slower effect on the wine, but can still overwhelm if left in too long. Avoid heavy toast oak unless you like the burnt rubber effect.

You have more flexibility with oak additions if the wine is to be aged for three years or more as it will lessen and integrate. Consider though, that curing the problem of too much oak in the wine can be difficult. (See Blending below). If the problem is not too severe, fining with casein, which is derived from milk, may reduce the oak taste and aroma without the loss of too much color and aroma.

Sometimes a wine can have too much skin contact and become “over-extracted” with the tannins overwhelming the fruit and clashing with the acids in the wine. Once again fining agents can reduce the tannin levels. Egg whites are commonly used in Europe, especially in Bordeaux. I find that tricky. Gelatin or casein works well, if used in moderation. If your color is strong enough, bentonite will strip out excess tannins.

Tannin comes into a wine through contact with the skins. This is true even of white wine, which is why skin contact is limited. In red wine, contact with the skins is crucial, especially before fermentation begins. If there is a deficit, enological tannin powder can be added before and after fermentation. Enological companies sell tannin powder that will integrate into a finished wine. Again, bench trials are something you should consider.

Blending

Blending is a process of combining wines to correct a flaw or to increase the depth or character of your wine. In many parts of the world blending is standard practice. Think Bordeaux, where Cabernet Sauvignon, Merlot, Cabernet Franc, and Petit Verdot, amongst other varietals, are the main grapes. Cabernet Sauvignon adds tannin, powerful fruit and acid, whereas Merlot adds elegance and mid-palate flavor. Cabernet Franc has some of both and extends the flavors. Petit Verdot adds a deep color.  These combinations create a wine that is better than the sum of its parts. So, you don’t need a flaw to blend, only an artist’s appreciation of what each grape can provide in the blend. Sometime a wine just needs a little help. Blending can provide that.

Blending is also used to correct an imbalance in the wine’s flavor or structure. For instance, this year I experimented with adding New York Cabernet Franc to California Merlot. The sugars in the Cabernet Franc were a bit low at about 20 brix. The Merlot had 25 brix. There would not have been enough sugar to create appropriate body in the Cab Franc. On the other hand the Merlot’s sugar level would create a wine with alcohol too hot for my taste. Combining the two produced a desired 23 brix without sugar additions. So too, the high acid Cab Franc balanced out the low acid Merlot to produce a much better overall TA which needed only slight adjustment.

Post-fermentation, these two flawed wines could have been blended to achieve the same result. With bench trials to guide the additions, acid can be increased or decreased in a finished wine. A flabby wine can become an exciting wine. An acidic red can be tamed to allow the fruit to shine. Or small additions may allow you to bring the PH into a more stable zone with lower additions of sulfite needed, creating a longer lifespan.

Blending can also tame rough tannins, without having to use a fining agent that has the potential to also strip color and aroma in the wine. These tannins can be gently lessened while keeping the overall character in the wine. This is true also of wine that is over-oaked. Oak is like salt, a little goes a long way. You can lessen the impact of the oak without necessarily losing the character of the wine by combining it with an unoaked, similar wine. 

Clear, Correct and Combine!

Often we winemakers focus on the problems of fermentation and whether the wine has come to a “finished” state for bottling. Is all the sugar depleted? Is the malolactic acid fermentation been fully completed? We often overlook the few small corrections that may substantially improve the flavor and character of our wine. Before bottling ask yourself: Can this wine be better?