“I didn’t do a hard count, a cluster count,” Knotts said, as he looked at the growing mound of crushed grapes in the harvest bin.
He said the late freeze means fewer berries and fewer clusters. The rain this year neither helped nor hurt the harvest but did save some water.
“This year I never turned the irrigation on,” he said.
His drip irrigation system conserves water and is very efficient, however.
“The real problem in this area of Oklahoma and Texas is we don’t have cool nights,” Knotts said.
The grapes on the vine continue to metabolize sugar longer in the heat which means a slower ripening process.
“You want grapes to have a certain sugar content and maturity,” he said.
When the grapes are close to maturity, Knotts emails his volunteers. Harvest is set at maturity.
“Or when OU doesn’t have a home football game,” Knotts said. “Or when the cosmos comes together and there’s a late game, an away game or no game — no game is best.”
The buckets of freshly picked grapes are dumped into the crusher and destemmer which, yes, crushes the grapes and removes the bulk of the stems.
The crushed grapes stay in the harvest bin for four to six weeks to ferment. Fermentation is a chemical process that causes the fibrous materials — grape skins, seeds and small pieces of stem — to rise and form a cap on top of the juice.
Knotts goes in and pushes that cap down several times a day. Using his bare hands allows him to feel for hot spots and manage the temperature through mixing to keep it homogenous. The air conditioner in the winery cools the room to 64 degrees.
“The fermentation is around 80 degrees,” Knotts said.
Pressing the cap down into the juice also releases sugars and creates a surge of fermentation.