A Cool Summer and Its Consequences: What Winemakers Need to Know
Cooler-than-average or damp growing seasons may seem promising at first, offering extended hang time and slower ripening. But these conditions often bring an entirely different set of vineyard and cellar challenges, from disease pressure to delays in ripening, making it essential to plan ahead to protect your wine.
What’s the Problem with a Cool Summer?
Unexpectedly cool temperatures, especially when paired with humidity or late rains, can lead to several problematic outcomes in the vineyard:
- Delayed Ripening: Grapes take longer to reach phenolic maturity, and sugar accumulation may lag behind flavor development. This can result in unbalanced fruit and longer hang time on the vines.
- Increased Disease Pressure: Mold and rot, particularly botrytis and powdery mildew, thrive in cool, moist conditions. This can lead to fruit degradation, off-aromas, and increased microbial load in the winery.
- Thin Skins, Low Brix, and High pH: These are often the hallmark of a cool year, particularly for red varieties. Wines made from such fruit may suffer from color instability, microbial instability, and less structure overall.
What This Means for Winemaking
Winemakers should be prepared for fruit with compromised integrity and an increased microbial load. In the cellar, this can manifest as:
- Stuck or sluggish fermentations due to low nutrient content or high biogenic amines from moldy grapes.
- Oxidation and color loss, especially in red wines.
- Higher risk of spoilage organisms such as Brettanomyces, Lactobacillus, or Acetobacter, especially in cases of high pH.
Tools from ATPGroup to Help You Mitigate Risk
ATPGroup offers a portfolio of products and solutions designed to help you navigate the complications of a cool and potentially wet vintage:
Microbial Control
Vin-Chito
A high molecular weight chitosan derived from Aspergillus niger, Vin-Chito helps reduce populations of Brettanomyces, Acetobacter, and Lactobacillus. It is ideal for fruit compromised by mold or rot.
Potassium metabisulfite
Make sure you have enough of this workhorse cellar chemical on hand to meet your anti-microbial and antioxidant needs.
Good microbes
Inoculate with bioprotection and a strong fermenting SafOeno™ yeast from our partners at Fermentis to ensure a vigorous and complete fermentation.
Color and Oxidation Management with Tannins
ATPGroup offers a diverse portfolio of wine-specific tannins to help stabilize color, improve mouthfeel, and protect against oxidation, especially in fruit affected by mildew or botrytis.
Color‑Tan
A high-antioxidant fermentation tannin made from condensed and ellagic tannins. It improves structure, enhances mouthfeel, and rapidly binds unstable proteins. Excellent for stabilizing color in red grapes with botrytis pressure.
Tannica Vintage
A natural chestnut tannin with high anti-oxidasic capacity. Use during fermentation or maceration to improve antioxidant capacity and preserve color in red, white, and rosé wines.
Gallic Tan
A powerful hydrolyzable tannin that reduces the activity of laccase and tyrosinase, lowering the risk of oxidation and related spoilage in grapes.
Cleaning and Sanitation
Causticlean K
A potassium hydroxide-based, chlorine-free alkaline cleaner for tanks and CIP systems. It is low-foaming, sodium-free, and safe on soft metals—ideal for sensitive winery environments.
Foam Control V
A non-silicone, vegetable-based anti-foam compound that prevents excessive foaming during fermentation or cleaning. It also helps preserve foam-positive proteins and improves cleaning efficiency.
Plan Ahead, Stay in Control
A cooler vintage doesn’t have to mean lower quality. With the right products and support, you can control microbial risks, preserve color and aromatics, and improve wine stability from harvest to bottling.
ATPGroup is here to help. Our experienced enology team can work with you to assess fruit condition, make product recommendations, and tailor solutions to your winemaking style. For more information, contact your ATPGroup Enology Products Specialist or call (707) 836-6840.