2018 Harvest & Winemaking: Part I

This year we decided to go big! Ordering nearly 300 lbs of grapes from our local farmer. Two weeks ago we picked up 90 lb of Cabernet Franc, 90 lb of Zweigelt; and 100 lb of Noiret. Harvest pickup day is The farmer picks, crushes and de-stems the grapes for us (we have done it ourselves too). We bring our food grade 20 Gallon Brute Totes with us and he either has them crushed already or we crush them when we get there. This year he already had the Zweigelt crushed, but the other two varietals had been picked that morning.


After we bring the grapes home, the first day is more of a science project than anything. We have to test all of our wine must (grapes, juice, skins, seeds, etc.) for specific gravity, titratable acid, and pH. For this year’s batch, I was a bit disappointed in the harvest since it seems like the grapes were picked a bit early. When the grapes are picked before they are ready, you will end up with higher acid and lower sugar in your must. Which can lead to a more astringent taste (acid) and low alcohol (sugar) . Below is the chart of different metrics for each grape. Generally speaking for reference we were looking for >1.092 for Specific Gravity (SG) and between 6-7 for titratable acid (TA); pH of around 3.3-3.6.

  • Zweigelt
    • pH – 3.8
    • TA – 6.5
    • SG – 1.082
      • Added 2.2 lbs of sugar
  • Cab Franc
    • pH – 3.2
    • TA – 8.5 (too high!)
    • SG – 1.086
      • Added 1.6 lbs of sugar
  • Noiret
    • pH – 3.2
    • TA – 8 (too high!)
    • SG – 1.074
      • Added 4 lbs of sugar
Chemistry Stuff!

**Vines to Wines is a good book for Winemaking – we always keep it on hand!

At this point we actually let everything just sit outside in the garage overnight. We add enough sulfites to kill the wild yeast, and let the sugar, sulfites, and juices commingle for our next specific gravity test the next day. We want to give the sulfites time to work their magic and sugar time to dissolve and disperse. Sugar is basically the food for the yeast, which determines the level of alcohol which results in giving the wine more body (and can make you drunk!). Adding sugar to wine must is called chaptalization – which is frowned upon by some pinky pointing winos, but necessary for many northern wine regions to produce wine with high enough alcohol. Up here in Michigan, we have a farmer that is pretty conservative with when he harvests his grapes and we have always had to chaptalize – even if it is just a little bit. This year we had to add much more than prior years due to the early harvest, which was probably a good thing since we had about a week and a half of rain in the two weeks after we picked up the grapes, so they probably would have swollen and split due to the rain.

Chaptalization of the Noiret must

After 24 hours, we brought the totes inside to let them warm up to room temperature. Once ready, we pitched the yeast – we used the Lavlin Bourgovin RC 212 as we have had really good luck with in for red wines in the past.

Part One Resources: