Ask Wine Wizard

Pressing my grapes seeds can result in undesirable flavors in the wine


Brian Aziz — via email asks,

When pressing my grapes I am aware that pressing the seeds can result in undesirable flavors in the wine. I have always been careful not to over-press my grapes but this year I pressed until the pulp was dry then examined it and there didn’t appear to be any broken seeds in the pulp. Is it possible to exert enough pressure with the typical home basket press, to rupture the seeds?

Heavy pressure I’m so pleased you’re paying such attention to detail in your winemaking. Absolutely we need to be concerned about extracting bitter seed tannins in our wines and during pressing we must certainly be vigilant. This is when the pressure of pressing can sometimes extract a number of bitter phenolics from seeds and skins; a few of these compounds can contribute extra tannin and “grip” to a wine, but too much can push a wine over a bitter and gritty cliff! This is why, towards the end of pressing, many winemakers take a “press cut” to separate out the last 10–20% or so of the wine that comes out of the press. Often we’ll add it all back in, but it’s nice to be able to keep it separate for later evaluation. Taking press cuts allows you more control in the balance between wanting to make sure you squeeze out every last drop but also wanting to be left with the best wine possible. You’re also on to something when you’re guessing that a typical home basket press is
Response by Alison Crowe.