Topic: Winemaking Science
Sulfur Dioxide: Fact and Myth
MEMBERS ONLYWinemakers have a lot of misconceptions about sulfur dioxide and its use in winemaking. Though somewhat controversial, longtime wine educator Clark Smith shares his views that are backed by science.
The Science of Winemaking
MEMBERS ONLYThere is a lot of chemistry involved in winemaking — the better you understand it, the better chance you have of consistently making quality wine. Learn the role science plays and how to use it to your advantage when it comes to Brix, pH, titratable acidity, and more.
Protection from the Elements
MEMBERS ONLYHeat (protein) and cold (bitartrate) stability issues in wine cause off-putting aesthetic defects that are often brought to light after the wine is in the bottle and undergoes a temperature swing if not taken care of during bulk aging. Learn how (and if) you should take these heat and cold stabilization precautions at home.
A Nitro Boost: Nitrogen’s role in primary fermentation
MEMBERS ONLYWine was made for millennia with little intervention from humans. But let’s be honest, we have no idea how those wines tasted. Today we know that yeast create the wine and keeping them happy is crucial for producing good wine. Learn how nitrogen plays a pivotal role.
Volatile Acidity Basics
FREEIt’s a dirty phrase in most winemaking circles, but volatile acidity
is found in all wine and having a little can actually add complexity
to a wine. Get the scoop on volatile acidity
Spit Or Swallow? Health benefits from spitting wine
FREEOne reader who is also a medical doctor discusses the potential health benefits of wine tasters who swish and spit their wines. It may be one of the healthiest things you can do . . . but that doesn’t mean he abides by the spitting aspect.
Maceration Enzymes: Making the most of these additions
MEMBERS ONLYThere are a lot of enzyme products available to winemakers, but in general they can be broken into just a few classes. Learn when and why a winemaker might use some of these various enzymes, especially during maceration.
Trying to Work With Grape Juice That is Amiss
MEMBERS ONLYWell, your grape or juice source really put you in a bind. Those are some of the most unbalanced initial numbers I’ve ever seen, and I would seriously consider getting your juice from another source next year. Numbers like that — with the acid being so low and the Brix simultaneously being low may be,
The Role of Varietal Thiols in White Wines
FREEVolatile thiols are delicate but powerful aromatic compounds released during fermentation. Through careful techniques and yeast selection, these thiols can be both preserved and enhanced to create an aromatic wine that pleases the senses.
Additives to Impact Phenolics and Tannins
FREEIn previous articles on phenolics I have reviewed the basic structure of the most important phenolic compounds in wine production and discussed how different processing and equipment options can impact the type
Tannin Additions: Tips from the Pros
MEMBERS ONLYA grape’s tannin structure is impacted by varietal, terroir, and growing conditions. Sometimes, grapes lack the tannins desired, and when that happens winemakers have the option of techniques to maximize extraction, adding tannins, blending, and more. Three pros share their approach in this issue’s “Tips from the Pros.” Phil Plummer, Winemaker at Montezuma Winery in
Phenolics in Red Wines
MEMBERS ONLYIt is in red wine production that the impact of phenolics is most influential in determining wine style and quality. We know that what is happening in wine on a chemical basis will influence choices regarding processing options and timing of activities for different wine styles. In this article, we’ll explore how polyphenolics are extracted
Testing for Titratable Acidity
FREETitratable acidity, or TA, is often viewed as a more advanced test, but it shouldn’t be. With a simple kit and a good pH meter, anyone can measure TA in any wine. Bob Peak has some straightforward advice for winemakers to help you bring balance to your wines through TA.
Phenolics & Tannins in White, Sparkling & Rosé Styles
FREEPolyphenolics are usually associated with red wines, but there are definitely processing choices and stylistic options where polyphenolics play a role in whites, rosé, and sparkling wines also.
Phenolics and Tannins
MEMBERS ONLYAn understanding of what is happening in wine on a chemical basis can be very useful in influencing choices regarding processing options and timing of activities for different wine styles. Unfortunately winemaking chemical nomenclature, chemical analyses, and interpretation of results can be daunting for those without a background in chemistry. Perhaps one of the most
Testing for Malolactic: Don’t be in doubt
FREENot all wines should go through a secondary malolactic fermentation (MLF), but for all wines that do undergo this fermentation, testing should be performed since these secondary fermentations can get stuck. Learn some of the basics of performing your own MLF test with paper chromatography.
Oxygen Management for Home Winemakers
MEMBERS ONLYOxidation is one of the most common faults among home (and pro) winemakers. Learn how to protect your wine against the detrimental effects of oxygen.
Oxygen Management for Home Winemakers
MEMBERS ONLYOxidation and oxidatively-driven degradation have been a constant plague on winemakers since time immemorial. Even today, with advancements in science and production, it continues to haunt producers of all sizes and styles. Oxygen exposure is the driving force behind volatile acid production, mycoderma formation (film yeasts), acetaldehyde production, depletion of free sulfur dioxide (SO2), browning,
Lower Alcohol Wines
MEMBERS ONLYThe warming climate and the rise of mean temperatures during the growth season of grapes, which has been evident in these two last decades, has caused the rise in sugar content and the decrease in acidity of musts. This has already become an issue winemakers are aware of and some are trying to compensate for,
At Home in the Wine Lab
MEMBERS ONLYOver the course of an individual’s early experiences as a home winemaker, one will have a few pitfalls and batches that may not be “quite right.” Wines may be perceived as out of balance or to have mild flaws. Many of these balance and flaw issues can be addressed or avoided with some simple lab
pH Reanalysis
MEMBERS ONLYThe answer to your question depends on the size of your batch. The bigger your batch, especially if it’s must all mixed together with juice and skins, you need to mix quite a bit longer. Let’s say for example you have a 5-gallon (19-L) carboy of Chardonnay juice and you are adding 1 g/L tartaric
Understanding YAN
MEMBERS ONLYIf you want to make good homemade wine, you should learn to manage your wines’ YAN — yeast assimilable nitrogen.
Calculating ABV
MEMBERS ONLYThis is a great question. Luckily the answer is simple. You still only calculate potential alcohol based on the original Brix reading. “Negative Brixes,” or when the density of your fermented solution reads below the 0.00 °Brix mark on your hydrometer, happen because they are just that: Fermented. Alcohol is much less dense than water
The Facts About Wine Headaches
FREEI’ve seen a few of these kinds of articles (ahem, I mean advertisements) floating around on the internet and it always results in an epic Wine Wizard “facepalm” upon reading. For starters,
Dealing With A Copper Problem
MEMBERS ONLYThat’s too bad that you added more copper sulfate than you intended to. Copper is an effective, legal, and ancient (the Romans knew about its curative powers in winemaking) tool for reducing (no pun intended) stinky rotten egg defects. Hydrogen sulfide is often the culprit and ionic copper, delivered in the form of copper sulfate