White Wine Case Study

white wine webI planted my hobby vineyard in 1999 and made my first wine in the 2002 vintage. I have 125 vines of Chardonnay and 125 of Pinot Noir planted on 1⁄3 acre (0.13 hectares) in Sonoma County, California. I am located in the soon-to-be (hopefully) AVA of the Petaluma Gap, a cool-climate sub-region of the larger Sonoma Coast appellation. The Chardonnay that I make every year is remarkably consistent in its overall character. While I have not deliberately arranged variables to construct a study of my wine, I do take notes every year with harvest data, fermentation choices, and tasting impressions. I also enter my Chardonnay in various home winemaking competitions. The notes and score sheets together give me an irregular but informative look at the effects of winemaking decisions. In this story, I’ve compiled my years of winemaking and scoring notes to construct a profile of my house Chardonnay.

During 13 years of making wine from the same vines, I have made changes and comparisons with a number of variables. These include degree of ripeness (as °Brix) at harvest, choice of yeast strains at fermentation, oak addition decisions, malolactic inoculation, and the addition of specialized fermentation products. This last group includes sacrificial tannins during fermentation, enzymes, and specific inactivated yeast nutrient products. In my general nutrient program, I have consistently used Fermaid K complete nutrient product and sometimes supplemented with diammonium phosphate (DAP) as needed.

Bobs VineyardpH and Brix

Year in and year out, I produce a very consistent wine. The pH level is always lower than “ideal” figures cited in winemaking literature; I generally measure between 3.1 and 3.3 pH. Total acidity (TA) is correspondingly high; from 7.5 to 8.5 g/L most years. Brix levels have usually been between 21° and 22°, although as noted earlier, I have experimented with that. After a few low-Brix harvests, I decided to see if I could push higher. Of course, growing conditions and weather have a strong influence on timely ripeness each year. However, as the grower, there are steps you can take to assure more even and predictable ripening. After harvesting at 20 °Brix in 2002 and 21.4 °Brix in 2003, I began dropping fruit after veraison in following years throughout the vineyard. Clusters that appear less mature or seem too numerous on any one vine are cut off, allowing the vine to more evenly ripen those that remain. Despite my best efforts, harvest Brix continued to hover around 21.5 °Brix for several years. The wine remained crisp, bright, notably acidic, and a bit “lean.” Competition wine judges used descriptors like lemon and grapefruit, with some even saying it seemed more like Sauvignon Blanc than Chardonnay. Finally, with the help of an excellent growing season and by delaying my harvest, I brought in my 2014 crop at 24.8 °Brix! That wine still has the bright, citrusy character typical of my vineyard, but it also exhibits noticeable alcohol. Although it has garnered two bronze medals in the competitions it has been in so far (the Sonoma Marin Fair and the California State Fair), judges have made comments identifying it as somewhat hot and a bit harsh in the finish. They are right! Compared with the 2012 and 2013 vintages, both of which came in between 21 and 22 °Brix, it is distinctly rougher on the palate. Experiments in trying for higher ripeness, with this variety in this vineyard, have convinced me to reverse course. I am back to looking for a harvest reading of 21.5 °Brix or thereabouts and not following the New World trend of ever higher sugar levels. I have previously won gold medals — and even a best of show — with the lower Brix wines and have decided that is the right harvest choice in my vineyard.


My yeast experiments have generally been directed toward achieving balance in my Chardonnay, given that I expect the high acid and low pH noted earlier. My first few vintages were fermented with Lalvin QA23. Lallemand notes low nutrient requirements and good tolerance to low temperatures for this strain. Since I do not have heat in my little wine barn in the backyard, that temperature tolerance was attractive. Since there is no home test for nitrogen nutrient status in must, it seemed prudent to select a low-nutrient-demand yeast. Those wines, though, were quite lean and had the noted Sauvignon Blanc character. As I learned more about grapes and wine, I noted that QA23 is also listed as producing large amounts of the enzyme beta-glucosidase, allowing the release of bound terpenes in aromatic varieties. Chardonnay is not one of those varieties and the juice does not carry a high concentration of bound aroma compounds. I decided after a couple of vintages to look at other choices. I next settled on Enoferm M2. Fermentation could be a bit more problematic as nutrient demand is high and temperature control may be needed during white wine fermentation, but the ester production is neutral. More important, Scott Labs notes that the strain is recognized for, “accentuating volume in the mouth.” I was very happy with the results with M2 and felt that I got past some of the leanness of my typical profile.

Several other home Chardonnay makers told me that Enoferm D47 would produce wine superior to that from M2. Scott Labs says D47 was selected for barrel fermentation of full-bodied Chardonnay, so it sounded promising. For the 2006 vintage, I carried out a side-by-side parallel study. I inoculated two carboys of juice with M2 and two more with D47. I followed my usual nutrient program and kept the room near 60 °F (15.5 °C) . After racking to topped-up secondary containers, I allowed the two versions to clarify for three more weeks. At that time, I thiefed out samples of each and conducted a tasting with my wife, Marty White. The D47 wine had light floral aromas and a distinct grapefruit note. It was crisp and refreshing and the grapefruit note followed into the flavor. With the slight fizziness of a very young wine, it reminded Marty of the grapefruit soft drink Squirt. The M2 wine had rounder, tropical fruit notes in the aroma and the flavor. Our descriptors included pineapple and melon, along with some citrus notes. We both found it superior to the D47 wine. We tried a blend as well and found it to be almost as good as the M2 alone, although not quite as tropical. In the end, I blended them for bottling. I think the Scott Labs description of D47 is simply inappropriate for my vineyard. I am not going to produce a rich, full-bodied Chardonnay in my cool location and the yeast alone cannot make up for the growing conditions. The M2 is a better match and I have stayed with it ever since.


Since so many California Chardonnay wines are overtly oaky, I decided I wanted to see how that would work with my wine. I conducted my experiment with a hectoliter barrel (100-L/26-gal.) made from American oak with a medium-plus toast. I intended the barrel primarily for aging Pinot Noir, but decided to barrel-ferment that year’s Chardonnay in it first. I soaked up the barrel, funneled in the clarified juice, and inoculated with M2. Fermentation proceeded well, but I knew the rest of the “barrel fermented” profile included lower TA than I usually encounter and also usually includes a notable buttery malolactic component. My harvest TA came in higher than usual at 9.9 g/L, so I knew I had to do something about it. I deacidified with 3.4 g/gal (0.9 g/L) of potassium bicarbonate to reduce TA by 1.0 g/L. That would still leave it high for this wine style, but I try to resist over-adjusting my wines when possible. I inoculated in the barrel with Wyeast liquid malolactic culture. I bought a new 5⁄8-inch (1.6 cm) diameter poplar wood dowel and sanitized it for use in lees stirring. Twice a day for the next several weeks I stirred the lees (“bâtonnage” in French) to try to enrich the mouthfeel of the wine. After that, I racked it to carboys and kept it at 55 °F (13 °C) for aging. In March, while testing sulfur dioxide levels, I also did a tasting. At that point, I noted a golden color (darker than usual) and promising oaky, buttery, and vanilla aromas. It also had creamy, oaky flavors while still exhibiting the “house” acid structure. I maintained the sulfur dioxide levels, racked it one more time, and bottled it in May. Upon tasting it again, my notes begin to reflect some doubt. It was darker, notably oaky, and fruitiness was subdued. Looking back, my ominous comment at this point was, “We’ll see!” As often happens, the fruit notes continued to decline in bottle. After a few months, it was mostly a combination of oak and acid. By the time we were drinking the following 2011 vintage, the barrel-fermented 2010 was becoming an unloved orphan. While we did finally consume all of the 2010, it is not an experiment I will repeat.


While I had used general-purpose pectic enzymes to improve juice yield in some previous vintages, in 2011 I applied Lallzyme Cuvée Blanc for the first time. This enzyme blend includes pectinases, but also is high in beta-glucosidases to aid in releasing bound aroma compounds. Intended specifically for use during skin contact, it can help release aromas that would never be available in the juice after pressing. Beneficial to aromatic varieties, it helps boost aromatic complexity in Chardonnay as well. After pressing the juice, I applied two more products. The first of these was a sacrificial tannin, FT Blanc Soft from Scott Labs. It is based on gall nut tannins rather than oak wood tannins and does not impart oaky character. It does, however, help protect against oxidation and enhances mouthfeel. The other new addition was the specific inactivated yeast nutrient OptiMUM-White from Lallemand. Although classed as a nutrient, this product does not add significant nitrogen nutrition to the must or juice. Rather, with high concentrations of glutathiones (a naturally occurring powerful antioxidant) and polysaccharides, it helps inhibit browning and preserves aromatic esters like grapefruit and passion fruit.

My tasting notes from 2011 begin in December. At that time I noted that the wine was clear, golden, and delicious. High acid as always, it was very much my house Chardonnay, but much better than the oaky 2010. By the time of a racking in February, it was a bit less fruity, but still exhibited solid Chardonnay character and my notes describe it as tasty and refreshing. I was pleased with the results and have used them in each vintage since.

My tasting notes for 2012 closely match 2011. There are also similarities in 2013, but that year I conducted one more experiment. Even though the barrel fermentation with malolactic inoculation and lees stirring in 2010 had not turned out well, I decided to experiment just with malolactic in 2013. After primary fermentation with M2 yeast, and using the wine enhancement products, I inoculated most of the vintage with Enoferm Alpha malolactic bacteria. Meanwhile, I kept one carboy of Chardonnay without inoculation, intending to use it later in a blend with some Chenin Blanc of the same vintage. Upon tasting them in February, I noted that the non-malo version was clear, pale, and had clean lemony flavors. The inoculated version was a bit more golden in color, also had typical “house” Chardonnay flavor, and was smoother in character. I described it in my notes as delicious!

My “longitudinal study” has left me with several lessons that I think any home winemaker can apply. The first is to take copious notes on every wine. As a corollary to that, taste your wine at every opportunity and write down your impressions. The next major lesson is to pay attention to how your grapes were grown and stay close to that character as you develop your wine. Also, with careful selection of products and techniques, and some trial and error, you can learn to get the best wine from your grapes.