Author name: Pete Lindgren

A stuck fermentation means yeast has stopped before the wine is dry — SG above 1.000–1.005 instead of the expected 0.990–0.996 finish. Here is how to diagnose it with a hydrometer, fix the common causes (temperature, high alcohol, nutrient deficiency, excess SO2), and restart it using a step-fed yeast starter. Cold-climate and chaptalized musts are especially prone.

Primary fermentation is the fast, vigorous first stage where yeast converts most sugar to alcohol. Secondary is the slow, airlocked finish. Here is exactly what happens in each stage, when to transfer, and what SG numbers to watch.

Campden tablets are pre-measured metabisulfite tablets used to add sulfur dioxide (SO2) to wine. One standard tablet (0.44 g) per US gallon delivers roughly 65 ppm SO2. Pete Lindgren walks you through crush additions, pre-bottling top-ups, equipment sanitation, and why you must wait 24 hours before pitching your yeast.

Potassium metabisulfite (KMS) is your SO2 source for protecting wine from oxidation and spoilage. Learn the exact dosing by weight, the pH caveat for free SO2, how to sanitize equipment, and how KMS compares to Campden tablets — with a clear gram-and-gallon dosage table.

Your grapevine looks dead after winter or a spring frost. Before you rip it out, do the scratch test: green cambium under the bark means it’s alive. Here’s how to check your vine, what winter-kill vs spring frost does, and how to prune and retrain it back to health.

Winterizing grape vines depends on what you’re growing. Cold-hardy hybrids like Frontenac and Marquette survive unprotected in Zone 3-5. Tender vinifera and half-hardy hybrids need root mulching, cane burial, or geotextile fabric. This guide covers every method, when to apply protection, when to remove it, and the fall mistakes that undermine cold hardiness – from a Zone 4 Wisconsin grower compiling 12 years of experience and UMN/Cornell extension research.

Brix stuck at 16-18 and frost is coming? Here is exactly what to do — pick timing, chaptalization, wine style options, and how to prevent it next season. Cold-climate Zone 4/5 guide from a Wisconsin home vineyard.

Chaptalization means adding sugar to grape must before fermentation to raise potential alcohol — not to sweeten the wine. For cold-climate growers in Zones 3-6, where grapes often ripen below 20 Brix, it’s a practical necessity. Learn the math, the step-by-step process, and how much is too much.

Grape must is the freshly crushed mixture of grape juice, skins, seeds, and sometimes stems — the raw material yeast turns into wine. Learn how it is made, how red and white winemaking differ at this stage, and how to measure and adjust must before fermentation.

Cold-hardy hybrids like Frontenac, La Crescent, and Marquette often arrive at harvest with TA of 10-16 g/L — the defining winemaking challenge for northern home vintners. Learn how malolactic fermentation, chemical deacidification, cold stabilization, and blending work together to bring these wines into balance.

Wondering which grapes actually survive Zone 4 winters? This guide rounds up the proven cold-hardy varieties — Marquette, Frontenac, La Crescent, Valiant and more — grouped by use, with honest notes on which popular grapes are really Zone 5 picks that struggle without protection.

Marquette and Frontenac are the two flagship cold-hardy red wine grapes from the University of Minnesota. Both survive brutal northern winters, but they differ in hardiness zone, acidity, and wine style. Here is a side-by-side comparison to help you decide which one belongs in your vineyard.