Making White Wine
the light-bodied aromatic style
September 2010 revision
The style and the appropriate grapes
If you have tasted a good Riesling or Gewürztraminer, you know what the light-bodied aromatic style of white wine is all about. Compared to an oaky Chardonnay, these aromatic wines: are higher in acid and lower in alcohol, use no oak, avoid malolactic fermentation (MLF), and usually have some residual sugar to balance the higher acid. The keys to making this style of wine are a good yeast, cool fermentation, Lysozyme, careful fining, a good acid-sugar balance, and early bottling.
Gewürztraminer and Riesling are almost always made in this style. Grapes like Chenin Blanc and Pinot Gris are usually made in this style. Some grapes, like Sauvignon Blanc, go either way. On the aromatic side, there is the high acid, New Zealand style with its gooseberry and cat's pee flavors. The alternative is the Fumé Blanc of California with more tropical fruit flavors and oak. Both are distinctively Sauvignon Blanc and both can be wonderful wines, but the California grapes were riper and the wine was aged on its lees in oak barrels.
Almost any white grape can be in the aromatic style. Even Chardonnay (which commonly comes to us in the high alcohol, full-bodied, oaked style) can be made in the aromatic style with great success.
It is probably safe to say that the aromatic style is the most common style of white wine and it has been increasing in popularity in recent years.
The rest of this note explains the main steps in making this style of wine. It assumes you are starting with settled juice. To have the best chances of success, you should know the following about your juice: Brix or sugar level, TA and pH, and YAN (yeast available nitrogen).
1. Getting started—protection and adjustments
Protecting the juice
Before you begin adjusting your juice for fermentation, you need to protect it. Likely some SO2 has already been added. If not, add 25 ppm SO2 (or more if your PH is 3.4 or higher) as soon as you can. If your juice is frozen, add this even before the pail is fully thawed. Also, add 0.1g/L of Lysozyme (see note on preparing Lysozyme.) One of the main enemies of the aromatic style is malolactic fermentation. Adding some Lysozyme now will reduce the ML bacteria level and help ensure a good feremnt. You will add more Lysozyme later.
Adjusting the acid
For an aromatic white wine, a starting TA of 8.0 and a pH 3.3 or below is about right. If the TA is below 7.5, add some tartaric acid. You can have too much acid too, but unless the TA is well above 9.0, it is probably not something to worry about at the beginning. Aromatic whites are characterized by higher acid levels. The acid increases the fruitiness of the wine. And the wines can handle this higher acid because they have a very low tannin level and they can be back-sweetened to achieve the right balance.
Normally, the white juices the club gets have good acid and pH levels. One exception can be Pinot Gris. You definitely want the pH of your juice to be below 3.5, so add whatever acid is necessary to get it there, or consider changing the style of wine you are making.
Adjusting the sugar
For an aromatic white, a starting Brix of about 22.6 (SG 1.095) is about ideal. Above this level, there is the danger the wine will begin to lose its fruity varietal character. But anything in the range of 19.3 (1.080) to 23.7 (1.100) can work fine depending on the variety. Remember that some of the best aromatic wines are quite low in alcohol and aromatic whites seldom benefit in a sensory way from high alcohol levels. If you are going to add water to reduce the Brix, do it now (use acidulated water unless you also have high acid). If you are going to add sugar, calculate the amount now, but add it later (in solution), as the fermentation is winding down (this helps to prolong the fermentation and is supposed to enhance flavor and body).
2. Yeasts and fermentation temperatures
Choosing a yeast
A couple of club tastings over the last few years have suggested that Vin-13 is the favored yeast for aromatic whites. It seems to lead to a fruitier aroma and taste than other common choices. And it is relatively easy to use because it has low nitrogen requirements.
However, there are other yeasts that also can work well. D-47 is an old favorite and widely available. And many people still swear by EC-1118, although Lallemand now recommends DV10 over EC-1118 as an all-purpose, no-problem yeast. All these yeasts have low nitrogen requirements.
Peter Brehm prefers VL1 or R2 for his German whites. In theory, VL3 should work better than VL1 for aromatic varieties. A Club taste panel almost unanimously preferred VL3 over VL1 in a tasting of two otherwise identical 2004 Chenin Blancs.
If you are fermenting a significant amount (say 200 lbs and up) of the same grape, you could ferment in smaller lots and use a different yeast on each one. This might add to wine complexity and it will help you decide what yeast you choose in future.
Read the instruction "Rehydrating Yeast." Do not automatically add yeast nutrient before the start of your fermentation.
White wines are almost always fermented cooler than reds, in large part because cooler temperatures are thought to produce better fruit flavors (they also produce more alcohol from the same amount of sugar). Lower temperatures are particularly important for aromatic whites. Some discussions of white wine making distinguish a European style of fermentation and a New World style. The European style uses a warmer fermentation (15-20°C). The New World style tends to be as cool as possible, with a view to maximizing fruit flavor.
A temperature of 10-15°C is the usual target for fermenting aromatic whites. Below 10-12° most yeast will do almost nothing, but they will not die either. With very low temperatures you may have bragging right about how long your ferment lasted, but it will not likely have had any impact on the quality of your wine. You want your ferment to last weeks rather than days, but not months.
The usual strategy is to get your must started at close to room temperature and then, in the next 24 hours, to gradually lower the temperature to your target. This allows the yeast population to build quickly. It then adapts gradually to a lower temperature and begins sugar fermentation at the lower temperature. See "Home winemaking strategies for keeping white ferments cool" for some of the techniques club members use to keep fermentations cool. Fermentations produce lots of heat, so you need to stay on top of temperature control.
Warm up the fermentation as it nears completion. This helps the fermentation go to dryness.
Club members differ quite a bit in how they physically contain their fermentation—at least they do initially. Some fermentation right in the pail (with lid sitting loosely on top) and move the wine to a carboy (with burper) when the fermentation is nearing its end. Others will do two or three pails at once in a 20 gal plastic pail (with lid sitting loosely on top) and move the wine to carboys (with burpers) as it nears the end of the fermentation. Others like to ferment in carboys at the outset. The choice may be largely a matter of convenience. The only general point of agreement is that a fermentation, before it gets to about 1.005 SG, should be in carboys with air-lock protection.
3. Feeding the fermentation
There is nothing unusual about the care of your yeast as they do their work in a cool fermentation. The only difference is that you will be spreading your Fermaid-K and DAP additions out over weeks rather than days. If you know your initial YAN (yeast available nitrogen) level, you should calculate all your additions at the beginning when you add the yeast and then make these additions when you get to the appropriate point in the fermentation.
4. Protecting the wine with SO2 and Lysozyme
After your fermentation has gone to dryness, you must move immediately to protect it. You have almost no grace period with the aromatic style because there are few tannins in the wine to help protect it from oxidation and you want to avoid an MLF at all costs. You need to add SO2 and Lysozyme.
Because the pH of aromatic wines is usually quite low, less SO2 is required to protect them. You want to make sure you add enough, but don't add too much. Excessive SO2 is immediately apparent on an aromatic white wine. Even if you don't get the characteristic "burnt match" smell, you will find excess SO2 completely masks the aroma. So use the chart for SO2 additions. You will be adding smaller amounts of SO2 as you get close to bottling, but the main dose comes now, as soon as the fermentation is finished.
The secret to a successful aromatic white wine is preventing MLF (malolactic fermentation) and you must do this immediately after your sugar fermentation is over. (A MLF is a bacterial fermentation that converts malic acid to lactic acid.)
The malic acid is an important part of the fruitiness of the wine. An unplanned malolactic fermentation in the carboy or bottle will almost certainly ruin the aroma and taste of your wine (think "dirty socks"). And if you have helped preserve a somewhat sweet white wine with potassium sorbate, you could end up with the dreaded "geranium" taint when the malic bacteria goes to work on the sorbate.
In the days before Lysozyme, the only way home winemakers had to prevent a MLF was to try to insure an inhospitable environment for the bacteria, which meant keeping the wine at temperatures below 15°C, with a pH of 3.1 or lower and free SO2 level of 35 ppm or higher. Riesling was one of the few grapes where you could hope to make this work regularly.
Fortunately, Lysozyme now provides a "silver bullet. Add 0.2g/L Lysozyme (or a bit more with pH or 3.4 or higher) as soon as your ferment is over and you are waiting for it to clear. (For more details on Lysozyme, and how to prepare it for use in your wine, see the note “Using Lysozyme.”)
If you suspect you have H2S issues (aromatic whites should smell fruity and pleasant right from the get-go, so if they don't, suspect the worst), you should deal with them immediately after the two protective steps just noted. This will probably involve using copper sulfate. You don't want to be adding copper sulfate close to bottling. For more on H2S issues, see "Understanding and eliminating sulfur-related aroma defects in wine."
5. Finishing your aromatic white wine
Generally you want to get aromatic whites into the bottle as soon as possible. They are fragile wines and there is little to be gained and much to be lost with bulk aging. You will want to let the wine sit for a few weeks once the fermentation is complete and you have added protection, simply so the wine can clear. It is fine to do this at room temperature, as it helps the CO2 escape. But once the wine is reasonably clear (which usually happens quite quickly, especially with the added Lysozyme), it is time to be moving the wine toward the bottle.
Finishing your aromatic wine for bottling involves several steps.
Getting rid of dissolved CO2
Wines finish fermentation supersaturated with CO2. Because aromatic white wines are bottled early, and are often kept cold, they may not get much natural opportunity to release this CO2. If you bottle with a lot of CO2 still dissolved in the wine, it will have a "spritz" when you pour it later, and this is generally considered an undesirable feature. Kit wines (which are also bottled early) advise a period of strenuous stirring of the wine in the carboy to help release the CO2. You can try something similar. Remember that you will release CO2 more easily at warmer temperatures, so let your wine come to room temperature first. Some of your process (such as stirring in finings) will also help CO2 escape. You can also bottle at room temperature to assist with CO2 removal. CO2 doesn't need to be removed all at once, but it is something to keep in mind during the process leading up to bottling. Always assess your CO2 levels at room temperature.
Fining for proteins—"warm stabilization"
If your wine has not cleared naturally soon after fermentation (many aromatic wines do clarify easily), you will want to fine before you filter. However, even if your wine seems perfectly clear, you should fine for proteins anyway. Proteins produce haze in wine only when they have had time to form longer chains. Protein haze is an aesthetic problem in all white wines, but especially so with the aromatic style because of the added Lysozyme, which is a protein.
If you are unsure whether your wine is going to be susceptible to protein haze, heat a sample to 80°C for 30 minutes. After cooling, look for signs of haziness. Fining for proteins is sometimes called "hot stabilization."
Fining with bentonite works to reduce proteins, and so do combination finings involving Kieselsol (Kiesolsol/Gelatin or Kiesolsol/Chitosan). You can find more information in the note "Identifying and preventing protein haze." Actually, home winemakers can't prevent protein haze because it it is impossible to know if most of the protein has been removed. But it is important to try. A bright clear appearance for a white wine is important.
All wines are supersaturated with potassium bitartrates at the end of fermentation and, over time, crystals ("wine diamonds") will form and precipitate. This is a problem in almost all wines, but particularly whites, where the results are so visible. Like haze, this is more an aesthetic issue than a wine quality issue, but careful winemakers try to get the crystals to form and precipitate before bottling. This is done by "cold stabilization."
The colder the temperature, the more quickly bitartrate crystals form and precipitate. The ideal procedure is to get your wine below 0°C (commercial wineries aim for -4°C) and keep it there for at least two weeks. If you can't get your wine this cold or keep it there, the process will take longer. (Given long enough, the crystal will even form and precipitate at room temperature, as they do in red wines.) After there is a layer of crystals at the bottom of the carboy (some crystals will probably stick to the sides of the carboy too), rack off your wine to a clean carboy.
NOTE on the timing of fining and cold stabilizing. Large commercial wineries will usually cold stabilize before they fine for final clarity and proteins. And home winemakers can do this too. But it is probably more sensible to combine these two steps. First fine, and then immediately start your cold stabilization. Usually this will mean you will get a firm layer of bitartrate crystals on top of the loose debris from the fining. This makes it easy to rack off perfectly clear wine.
Getting the acid-sugar balance right
Because cold stabilization will affect acid levels, it is best to leave balancing sugar and acid until it is almost time for bottling.
For many people, the flavor and body of aromatic white wines is enhanced by a bit of sweetness. This is because of the higher acid levels. There are two main ways to achieve this :
- Stop the fermentation as it nears completion, by chilling it and racking several times. This eliminates most of the yeast population—enough with SO2, you hope, to prevent the fermentation restarting. This is risky but it can work with yeasts that are less tolerant of high alcohol levels (these low-alcohol yeasts are hard to come by these days). Sometime you end up with a stuck fermentation, in which case you can make a virtue of necessity and claim the residual sugar as intentional.
- The more common and more predicable method is to ferment to dryness, add sorbate to stop yeast activity, and then back-sweeten with some reserved juice or a sugar syrup. (The “wine conditioner” sold in stores is simply a sugar syrup and potassium sorbate.)
Observe these principles in wines with residual sugar.
- Don’t over-sweeten. George Gibson thinks a sugar addition of 0.4g/L (and an eventual SG of about 0.997) is about right, but partly this will depend on your acid level. The more acid, the more sugar you can use to achieve “balance.” The most common mistake is to add too much sugar. This can taste find for a few sips, but soon grows tiresome. Also, young whites may still have a fair bit of dissolved CO2, which may make the wine taste less sweet than it will later.
- Use potassium sorbate. A bit of residual sugar (say to a SG 0.995) will probably not ferment later in the bottle, but no one is quite sure what the limit is. In the absence of sterile filtration, which is not really possible for the home winemaker, the only way to guarantee that your wine won't re-ferment in the bottle is to use potassium sorbate. Use 0.10-0.20g/L depending on your alcohol level. A higher level of SO2 is also wise. For more on sorbate, see the note on "Using potassium sorbate in white wines with residual sugar."
6. Handle gently and bottle early
Let's assume you wine is now protected, fined, cold stabilized, and balanced. You now want to get it in the bottle as soon as possible. There are no advantages to waiting with the aromatic style and there are dangers in waiting. These wines are very fragile. The sooner the wine is in the bottle the sooner it will get over bottling shock and begin to develop the full range of its flavors.
It is not necessary to filter wines, even white ones, but filtering will almost certainly enhance the clarity and appearance of white wines and it may even improve the quality. If you do filter your white wine, do so carefully. All white wines must be handled much more carefully than reds because they do not have the tannin to protect them from oxidation. This is especially true of light-bodied, aromatic wines, which do not even have oak tannins.
You should probably filter at room temperature. This will help in the release of CO2 and will limit the update of oxygen (oxygen dissolves more easily in wine at lower temperatures, just as CO2 does.
Final SO2 additions
Let's assume you put your filtered wine in carboys. The last step (say a day before bottling) is to add your final dose of SO2. Ideally, you will determine the existing SO2 level in your wine (using titrets) before making this final addition. Here are the steps:
- Consult the chart of SO2 additions to determine how much 10% sulfite solution you need to add for your pH level. Add 5-10 ppm more than this, to take account of SO2 loss that will occur in the bottling process. You might also add a little extra if you have significant residual sugar in your wine and you have not used sorbate.
- If you are bottling many cases of the same wine, consider adding more sulfite (an extra 10 ppm) to case you will open later. If your wine is in multiple carboys, this is easy to do. You just need to keep track of the wine that has the high sulfite level and make sure you open these bottles later. (For example, with five cases, number them 1/5. 2/5, and so on so you know the order to use them.)
You can bottle one day (or less) after you have made your final sulfite addition. Bottle at room temperature, taking care to minimize exposure to air. Try to store the bottle wine in conditions that are 15°C or cooler.
Johnson, Hugh, and James Halliday (1992). The Vintner's Art:
How Great Wines are Made. New York: Simon & Schuster. This book has
separate chapters on light-bodied aromatic and and full-bodied wooded whites.
Good reading and informative.
Based on a presentation by Rod Church for a Nanaimo Winemakers educational sessions in August 2004 and September 2005. Substantially revised by Rod for September 2010.