Harvest terminology can get confusing, so let's review the difference between juice, must, and fermenting must.

Juice is the liquid separated from the grape solids.

Must is the juice and solids together, including grape skins and seeds.

Fermenting must is juice or must that is actively fermenting. This can happen even if you haven't added commercial yeast yet—native yeast can get things moving on its own.

One important distinction is knowing when to pull your sample.

If you need a juice panel, get your sample to the lab early. Once a sample is above 1% ethanol, it no longer looks like juice to our Winescan and we can't accurately measure it as a juice panel.

Fermenting must samples require additional processing to temporarily stop fermentation before analysis. Carbon dioxide from fermentation can interfere with acid measurements, while actively fermenting yeast can rapidly consume YAN, making those measurements inaccurate.

A fermenting must panel includes:

• Glucose/Fructose
• Volatile Acidity
• Ethanol

This panel can help calculate potential alcohol and identify evidence of spoilage through VA.

Once fermentation reaches approximately 10% ethanol (around 5 °Brix for most wine types), we can run a wine panel regardless of malolactic fermentation status.

Not sure which profile to choose? Select fermenting must and we'll triage the sample and choose the profile that most accurately measures your sample.

During harvest, timing matters. Getting the right sample to the lab at the right stage helps make sure you're getting useful information when you need it.

Have questions about which panel you need? Give myEnologist a call or stop by—we're happy to help.

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