Topic: Winemaking Science
Yeast Nutrient Strategies
MEMBERS ONLYGrape juice is a pretty tough environment if you’re a yeast cell. The pH is low, there’s high osmotic stress (stress from the environmental conditions being such that the flow of water out of the cell is favored), and often, essential nutrients are limited. The abundance of fermentable sugars, however, makes life in these challenging
Simple Sulfite Wine Chemistry
MEMBERS ONLYThere is no denying: Sulfur dioxide (SO2) can be a source of headaches for winemakers — even without drinking any wine. Why does SO2 continue to be such a perplexing and confusing topic? All too often I am asked to help out with problems that seem completely unrelated to sulfite additions, though these are at
Techniques to Reduce Sulfite Additions
MEMBERS ONLYIn spite of their long history as wine preservatives dating to the days of the Romans, sulfites can receive a bad rap. Many suspect that sulfites cause headaches or believe that any preservative is harmful, and so, there is a strong push to eliminate — or at least reduce — the use of sulfites and
Tannin Chemistry in Wine
MEMBERS ONLYIt all starts with phenol. The tannins in wine make up one of the subgroups in a larger chemical family known as polyphenols. Those, in turn, are made up of phenol-derived molecules and additional carbon, hydrogen and oxygen atoms. While a winemaker does not need to know the chemistry of polyphenols and tannins to make
Using Winemaking Enzymes
MEMBERS ONLYMany winemakers shun the use of additives, including enzymes, to respect the wine’s “naturalness.” But juice is laden with natural enzymes, and once inoculated with yeast, fermenting wine is under the control of countless enzymes working hard to help convert odorless compounds into volatile, odiferous ones and create new ones, all of which will define
Understanding Oxygen and Oxidation in Winemaking
MEMBERS ONLYAs budding winemakers, one important principle we heed is protecting juice (must) and wine from oxygen’s baneful effects. But then we learn that yeast needs a “little” oxygen for a good fermentation, that reds benefit from “some” aeration, and that some white varietals can be subjected to lots of oxygen with no ill-effects while others
The Science of Food and Wine Pairing
MEMBERS ONLY“Carignane and goat cheese,” said Tony Ross, wine educator at Passalacqua Winery near Healdsburg, California. During a judging session for a local home wine competition, Tony and I were on the same panel. Between entries, I mentioned working on this “Techniques” column on pairing and he gave me his favorite recommendation. I went on to
Higher Alcohol Off-Odors in Wine
MEMBERS ONLYDid you ever create a wine that seemed more viscous than your typical wine, or which may have exhibited heavier fruity odors, or perhaps a solvent-like smell? The culprits may well be higher alcohols, also called fusel oils; all wines contain some at various concentrations. Higher alcohols in small concentrations can contribute positive aromatic characteristics
Managing Minerals in Winemaking
MEMBERS ONLYMineral deficiencies or excesses can become sources of frustration for amateur winemakers because minerals, metals and other ionic substances cannot be easily measured and their role in biochemical and chemical reactions can be quite complex. One of the most remarkable and visible effects of these substances are tartrate crystals resulting from wine containing a high
Yeast Impact on Wine Aroma and Flavor
FREEIf you are of the opinion that yeast selection does not matter and that the only role of yeast is to convert sugar into ethyl alcohol (ethanol), you may have been missing
Top 10 Winemaking Myths
MEMBERS ONLYAs in many fields — health promoting and weight-loss diets come to mind — that have grown from unfounded beliefs and around traditions, with newfound scientific knowledge proving or disproving long-held theories, the field of wine and winemaking has its share of myths, misconceptions and sheer quackery. To the uninitiated, enophiles can seem snobbish, often
Impact of Barrel Kinetics and Dynamics on Wine
MEMBERS ONLYOak barrels have long been used primarily for aging red wines but also to shape the style of certain white varietals, such as Chardonnay, into fuller-bodied wines. Oak wood imparts what is generally referred to as toasted-oak aromas and flavors, but more specifically, these include a varied set of volatile compounds, from aldehydes to oak
Gum Arabic: Winemaking’s Secret Weapon
FREEGum arabic can do so many great things for your wines, from improving mouthfeel, making a thin wine taste fuller bodied, rounding out rough edges of grape tannins, increasing persistence of bubbles
The Relationship of pH and Acid in Winemaking
MEMBERS ONLYHome winemakers know pH and acid are related when they make wine. Beyond that, the details sometimes get a little fuzzy. Shedding some light on how these important parameters are — and are not — linked to one another may help make better winemaking decisions. There are theoretical considerations from organic chemistry and laboratory analysis,
Using Outside Labs to Run Analysis Tests on your Wine
MEMBERS ONLYThere is lots of information out there about how to run various juice and wine analytical procedures at home if you want to do that. If you do not want to run the tests but you are interested in the answers, you may live in an area that has a commercial or university laboratory that
Co-Inoculation with Wine Yeasts and Bacteria
MEMBERS ONLYAsk 5 winemakers and you may get 6 opinions about co-inocculation. But what does the science say?
Oxygen Reduction in Winemaking
MEMBERS ONLYOxidation gets a lot of attention in winemaking — and it should! WineMaker magazine has covered oxidation issues from several different angles over the past few years. While some presence of oxygen in wine contributes positive effects, most of the time the home winemaker is excluding oxygen to avoid the browning, aldehyde formation, and spoilage
Year in a Life of a Wine: Part III (Testing & Adjusting)
MEMBERS ONLYIn the third installment of our year-long series about how homemade wine is made using home-grown grapes in Upstate New York, we check in on batches of red, white, and rosé wines happily fermenting away.
Volatile Sulfur Compounds and Hydrogen Sulfide in Wine
MEMBERS ONLYIf you have ever encountered volatile sulfur compounds in wine, of which hydrogen sulfide is the most common, you know how repulsive the smell can be. It can shoot one’s anxiety up a few notches because it always seems to catch you by surprise, and that the source of the problem is often difficult to
Wines, Naturally
MEMBERS ONLYDo you know the difference between organic, biodynamic, and natural wines? Learn what differentiates each term, plus ways to cut down on the chemicals in your winemaking process.
Home Wine Lab Testing: Tips from the Pros
FREELaboratory equipment for winemakers can be fiscally daunting, especially for beginning winemakers. That doesn’t mean that vital testing should be avoided. We asked two laboratory experts in wine lab services companies about
Impact of Oxygen on Winemaking
MEMBERS ONLYOxygen’s presence or absence at the various stages of winemaking can have extraordinarily important and lasting effects on what our wines taste like. Too much and you risk oxidation damage, too little and you risk reduction stink. The effects of oxygen on wine, much more so with red wines, may be the most complex and
Monitoring & Adjusting pH
FREEI am always surprised at how many winemakers — new and experienced alike — still make wine with absolutely no concern for pH. It’s akin to never checking your engine oil in
Enzymes for Hobbyists
MEMBERS ONLYWhen pioneers of winemaking like Louis Pasteur or André Tchelistcheff are mentioned, James B. Sumner is often overlooked. Nonetheless, this Nobel-prize-winning chemist (1946) set in motion the entire scientific field for today’s article. In 1926, Sumner successfully crystallized the enzyme urease and performed chemical analysis that demonstrated that urease is a protein. Not at all
Mastering Wine Acid Balance
MEMBERS ONLYFor the most part, winemaking is relatively simple, unless you run into some serious problem. But occasionally it does throw a curve ball at you with, for example, an acid level that’s just not to your liking. And this happens more often than not when making wine from grapes or fresh juice. Mother Nature can
