Welcome to Harvest Tips for Winemakers! This is a series of short videos summarizing some things to keep in mind as you go through harvest. We will try to do a new tip every couple of days throughout harvest. These will also be posted to our social media accounts (@vawrex) and YouTube Channel. Supporting articles will be linked below in case you want more information on any of these topics.
Happy harvest everyone!
Vineyards are variable places and the decision to pick the fruit depends on how well you sample all the variation that exists in the vineyard block. Follow these principles to make sure you aren't surprised when you see the fruit chemistry after you pick!
For more details on representative vineyard sampling, check out this article.
The decision to pick the grapes is one of the most consequential a winemaker will make. No matter how good your grape sampling is, the decision to pick the grapes always comes with some uncertainly. Measuring Brix is a good first step to understanding grape maturity, but with one simple addition, you can know much more about how ripe your grapes truly are. Consider measuring berry weight and calculating sugar per berry. If you want more informaiton on sugar per berry, check out this article in the VVA Grape Press.
In Tip #2 we talked about a few reasons you might let your red grapes hang a bit longer, including the decrease in pyrazine and evolution of berry aromas after the end of sugar loading. Another thing to keep in mind is the extractability of phenolics including anthocyanins and tannins. When you pick will impact the extractability of different types of tannin and drive wine style.
Happy, healthy yeast perform steady, complete fermentations, make delicious aromas and flavors from grape precursors without producing off aromas. When provided with adequate sugar, nitrogen, vitamins, and lack of stress in their environment, yeast can work magical transformations turning juice into wine. But sometimes these components are not all available in ample amounts in the grape. Nitrogen is a common deficiency, but it can be adjusted by the winemaker. Knowing how much nitrogen is in the juice or must allows the winemaker to decide if, when, and how much nutrient to add to a fermentation.
For more resources on YAN, check out these extension publications:
Most wineries have a pH meter for good reason; pH is a important indicator of grape ripening and contributor to wine stability. Knowing the pH of the wine is important for determining acid additions. pH is an easy measurement to take, but it is only accurate if the pH meter has been calibrated. The best way to ensure that an accurate pH is taken on time is to calibrate the meter first thing in the morning, before things get too busy. That calibration should hold all day. Every pH meter will have slightly different instructions for calibration. This video explains a few general concepts for pH calibration and troubleshooting.
For additional resources on pH calibration, see this extension publication: Winemaking basics: Can you trust your pH meter? (Oregon State)
If you need a protocol or calibration, CLICK HERE
Every vintage is a new adventure in Virginia. So far in 2023, we are experiencing a dry growing season with moderate temperatures. Some areas of the state are experiencing drought conditions. Several winemakers have reported picking red grapes earlier, and at higher Brix than usual. This video includes some things to keep in mind when fermenting red grapes with high Brix to help you make the most of this banner vintage.
During harvest, things can get really busy, and sometimes the lab work goes by the wayside. But no matter how busy you get, its always worth the time to monitor each of the fermentations every day. In this video we discuss what a normal fermentation looks like, and how recognizing deviations from normal allows you to intervene early to keep yeast healthy and happy, preventing off aromas and stuck fermentations.
There are many winemaking decisions that contribute to the final structure and mouthfeel of red wines, and getting the balance right isn’t always easy. This video outlines a few things to keep in mind as you manage tannin extraction in your red wine fermentations.
There is nothing worse than making a clean, delicious wine, putting it down in the barrel to age, then pulling the bung 9 monts later to find your wine has completely changed, and not for the better. This video outlines several things you can do at harvest to prevent microbial spoilage during aging.
Nobody wants to add more SO2 than needed, but there are many ways to interpret "what is needed". Defining the goals of SO2 addition and understanding how SO2 behaves in the wine will go a long way to helping you make sure your SO2 additions are achieving what you want them to!
For more details on the Blenheim SO2 Experiments:
Protect your hard work during harvest by preventing spoilage and faults with good hygiene practices in your winery. Now is a great time to think about your quality control protocols and review our top 10 hygiene tips with your team. We’ll have an ongoing discussion of various hygiene tips and projects throughout harvest and into the coming year.
For more information on winery hygiene:
Making Cleaning and Sanitation Practical for the Small Commercial Winery, Denise M. Gardner
This tip resulted from some feedback we heard last year from people using a new generation of rehydration nutrient that doesn’t require as many atemperation steps before the yeast is pitched. People using the nutrients loved how quickly inoculations could be made, but felt that the fermentations were sometimes slow to get started. Further investigation revealed the problem was actually in the lack of mixing that occurs with smaller inocualtion volumes. Whether you are inoculating with large or small volumes mixing after addtion can help ensure a homogenous fermentaiton and avoid several potential problems.
Wine acidity is characterized by pH and TA, both of which are commonly measured in Virginia wineries. Yet many of us remain a little bit fuzzy on how these measurements relate to one another, and what each means for the juice and wine. In this video clip (from the Virtual Sensory Session held in May 2024), Joy does her best to explain.
After Brix and pH, titratable acidity is the next most common measurement taken at harvest. Yet, there are a few barriers to making the most of this measurement. Instead of a video, we have three resources to help you measure and interpret TA data.
If you need a step by step protocol to follow, CLICK HERE. The protocol includes clear instructions as well as answers to some frequently asked questions about TA.
If you want to fine tune your own TA measurements, or want to understand how variable these measures can be, WATCH THE VIDEO of Dr. Patricia Howe explaining error in TA testing for the Virginia Wineries Association.
If you have mesured TA but are wondering what the result means, check out this GUIDE TO INTERPRETING TA RESULTS.
Whether to co-inoculate and the timing of bacteria addition are important decisions to protect your wine. However, there are several more factors to take into account. The following resources are meant to help you navigate the world of co-inoculation and make the best decision for your winery.