Have you had a white wine or a sparkling wine and thought to yourself, This is a bread bomb!
It smells yeasty and lands on your palate like a liquified brioche - bready and nutty with a creamy mouth feel. If so, there is every chance that the wine you just had has been aged sur lie.
Sur lie (pronounced sewr-h lee) is French for “on lees.” Lees are basically solid remnants from the winemaking process. There are generally two kinds of lees - gross lees and fine lees. Gross lees are mostly made up of grape debris. They are larger and tend to settle easily to the bottom of the wine. Fine lees refer to the sedimentary residue that consists primarily of dead yeast cells. They are smaller and can be easily stirred into a cloudy swirl before being drawn downwards by gravity.
Gross lees are often removed (or racked off) during the winemaking process. Prolonged contact with gross lees can contribute to off-flavors in wine. The funk may come from decomposing grapes, spoilage organisms, or excess sulfur found on the harvested grapes.
Lees left after racking
Fine lees, on the other hand, bring about desirable texture, flavors, and complexity to the wine. As yeast cells break down, they release mannoproteins, polysaccharides, fatty acids, and amino acids. Together these compounds contribute to the aromas and flavors of brioche, honey, and nut. They also create a buttery creamy mouthfeel while softening the tannins. As a bonus, fine lees are also reductive in nature and protect the wine from oxidation.
Bâtonnage, Stirring Up the Lie
There are two different methods for aging wine on lees: 1) keeping the lees at the bottom of the barrel, or 2) stirring the lees periodically to ensure homogenous and consistent contact with the wine. The latter approach is known as bâtonnage (pronounced bah-too-naj). It is believed that both processes give pretty much the same result with some stylistic differences. See the video on bâtonnage below.
When considering whether to practice bâtonnage, the winemaker has to determine how much lees contact is needed to bring out the desired characteristics in the wine. Major Burgundy house Maison Louis Latour uses little to no bâtonnage on their Chardonnay, believing that the lees-to-wine ratio in the barrel does not always require it. For wineries that choose to practice bâtonnage, they vary in how frequent and how long to stir the lees, walking the fine line between over and under-stirring.
Famous Sur Lie Wines
Sur lie wine aging is believed to date back to the Roman Republic era, as documented by Cato the Elder. In modern winemaking, the two regions famous for aging their wines on lees are Burgundy and Champagne. White grape varieties that benefit from aging on the lees are Chardonnay, Muscadet, Chenin Blanc, Pinot Blanc, Pinot Gris, and other crisp white wines with high acidity.
White Burgundy - Made with 100% Chardonnay grapes, white Burgundy is often credited as the originator of sur lie aging in modern winemaking. After harvest, the grapes are pressed, and the juice goes into the barrels without solid grape debris. Alcoholic fermentation starts in the barrels, followed by malolactic fermentation. Since there are no gross lees, the wine does not need to be racked till the next spring. After racking, some amount of lees is retained in the wine for another 10 to 18 months of barrel aging. Bâtonnage is optional.
2022 Maison Castel Chablis, a white Burgundy
Champagne - There are three main grape varieties in a Champagne - Chardonnay, Pinot Noir, and Pinot Meunier. With the exception of making a rosé Champagne, the harvested grapes are pressed and clarified to obtain a clear juice. The juice then goes into stainless steel vats to start alcoholic fermentation. The use of oak and malolactic fermentation is optional.
NV Laurent-Perrier Ultra Brut
When fermentation is complete, the wine is bottled with the addition of liqueur de tirage, which consists of still wine, sugar, and yeast. This starts off a secondary fermentation to create carbonation. Thereafter, the wine goes through sur lie aging in the bottle for a minimum of one year for a non-vintage Champagne and three years for a vintage Champagne. Bâtonnage is non-existent.
Aging on Lees in Barrel vs. Bottle
Wine aged on lees in the barrel benefits from the aroma compounds that are extracted from the oak. These add notes of caramel, vanilla, and spice. Additionally, there is space to maneuver a baton or any long metal tool to stir up the lees if bâtonnage is so desired.
As for aging wine on lees in the bottle, bâtonnage is virtually impossible. Also, there is also the challenge of removing the lees when aging is complete. This is achieved through a process called riddling, where wine bottles with lees are first placed at 35° angle on a wooden rack. The bottles are then gradually shaken and rotated at an increasing angle, with gravity pulling the lees to the lowest part of the bottles. When the bottles are virtually upside down, the lees that have settled in the bottlenecks are then frozen and removed. Voila!
Riddling rack
Now you have learned about a few things about lees - gross versus fine lees, to stir or not to stir lees, to age on lees in a barrel or a bottle. The next time you encounter a yeasty, bready wine, you may proclaim with confidence, “Surely, this wine is aged sur lie!”
Last October I posted about my first winemaking experience; well at least from crush through the primary fermentation and press. That was probably the most involved part of winemaking, when twice to thrice-daily punchdowns took place with constant measuring of temperature and Brix. That was when the juice was transformed from 'must' to wine as sugar got fermented into alcohol and carbon dioxide.
Secondary Fermentation
After the press, we moved into secondary fermentation of the wine in air-locked vessels. We used a 5-gallon glass carboy and three gallon jugs to use for top-up (I'll get into that later). This period was generally uneventful and less involved, but there were a few things that required attention.
Controlling the temperature.Malolactic (ML) bacteria, which was added to the juice the day before press, were quietly converting tart-tasting malic acids into fuller-bodied lactic acids. ML bacteria are sensitive to numerous factors (e.g. pH, SO2, and alcohol levels), but the one thing that worried me was my ability to keep the wine within the optimal temperature range (>70 degrees). The carboy and gallon jugs were wrapped in blankets, snugged in cardboard boxes, and gently warmed by a heating pad. My biggest fear was stuck fermentation since there were no easy tests to perform at home or measurements to track progress. I resorted mostly to prayers.
Lees left behind from racking
Racking, racking, racking.Even though most of the solid remains of the grapes and yeast (also known as pomace or marc) were removed during the press, there were still some remaining in the wine as it went through secondary fermentation. These are called the lees. Decomposing yeast in wine could cause off flavors. In order to remove the lees, we did multiple racking of the wine during secondary fermentation. Racking is the process of siphoning wine off of dead yeast into new containers.
We siphoned a total of four times; the first time was 24 hours after press, the next two were a week apart, and the final one was a month out.
Racking also has two other advantages:
It clarifies the wine. You could literally see that the juice got clearer after each racking. In many cases, clear wine is just a matter of aesthetic. If the wine tastes good, cloudiness may not indicate flaws.
When done correctly, racking can introduce controlled amount of oxygen into the wine. During the early part of secondary fermentation, oxygen has positive effects on unfinished wine by stabilizing the color and tannins. It allows the wine to mature gracefully and become more complex. In the later part of the secondary fermentation, caution is needed to minimize oxygen contact. If acetic bacteria is exposed to wine and oxygen, it will turn the juice into vinegar (acetic acid).
It is important to note that you will lose wine during racking due to spills and as you avoid siphoning lees. The loss of wine during racking may increase the air space between your wine and the airlocks. You can top up the carboy with wine from the jugs or similar store-bought wine (preferably same varietal and AVA). Alternatively, you can add sterilized marbles into your containers to raise the wine level. I personally put some of my top-up wine into a sanitized plastic container, squeezed out as much air as possible, and capped it. It worked!
Final Testing
After more than three months of secondary fermentation, we performed the final testing of our wine to check on sugar, acidity, and ML fermentation. During the primary fermentation, which lasted less than two weeks, I was constantly monitoring and measuring progress. For the much longer secondary fermentation, I really had no idea what to expect. But I was pleasantly surprised by the outcome.
Residual sugar was at 0.3%. This was probably the least of my concern since we pressed the wine at a really low Brix. Residual sugar over 0.6% is a concern for still red wine as it may cause re-fermentation in the bottle.
Measuring residual sugar in the wine
pH was 3.78. This was slightly higher (or less acidic) since harvest, which was at 3.53. But it was still within the normal range.
Titratable acidity (TA) was 7.3125. TA measures the amount of total acids and was higher than our reading during harvest, which was 7.125. It was a bit higher than I like, but not bad.
ML fermentation appeared to have completed. While not the most accurate way to test the concentration of malic acid, the chromatography test is cost-effective. The solvent used for the chromatography is extremely toxic, and the test takes several hours. After putting dots of wine sample onto a piece of chromatography paper, it was left in a big glass jar with the solvent and the lid closed tight.
With one exception, most of the wines appeared to have completed ML fermentation. Yellow patches indicated presence of acids. The top row of yellow revealed the presence of lactic acid, which is the goal of the ML fermentation. The bottom row of yellow revealed the presence of tartaric acid, which is also what we expected. Any yellow in the middle role revealed the presence of malic acid, which would indicate that ML fermentation has not completed. This would show that the wine has not stabilized and will need more time for ML fermentation to complete.
Chromatography test revealed that one of the wines still had malic acid
Bottling
Once the wines had passed all the tests, they were ready to be bottled. We got the bottles that we have saved up, cleaned, and sanitized. (We recycled bottles. If you buy new bottles, you can skip the above steps.) Sulfites were added to the wine just before bottling. Sulfites are a preservative and will keep the wine fresh. They are also anti-oxidants and will protect the wine from oxidation.
Adding sulfites to wine
Siphoning wine into bottles
Corking wine bottles
Finally, five months after harvest and crush, our first vintage was bottled and proudly named Abscession - a joke, as my husband was recovering from an abscess the day of the harvest. Special kudos go to my partner-in-wine, Alisa. That's her work on the label, making an access look classy. The wine will officially be released in the summer, so check back later.
Abscession 2016 Syrah
My Verdict: I am having so much fun learning about winemaking. It gave me a greater appreciation for wine. I don't think going commercial is my calling, but I'm planning for my next vintage already!
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