One of the critical steps in making any wine is pressing. There’s a few parts to it. First separating the free running liquid from all the solids, leaving wet skins seeds, any whole berries and stalks.
The second part is to get wine from the wet skins using a press. Aside from the type of press you use, the main options are the pressure you apply and the time you apply it for.
At one extreme you can wind the press right up to the highest pressure it can go as fast as you can. At the other you can slowly apply just enough pressure to squeeze the tiniest flow of liquid from the press, wait a while and then add a tiny bit more pressure.
Roberto Voerzio doesn’t even press his Barolo, only allowing the liquid to drain from tank overnight, the weight of the fruit in the fermenter providing the only very gentle pressing.
The faster and harder you press the more tannin you extract from red grapes.
With experience, constantly tasting what’s coming out of the press you work out just what the fruit you’re working with can handle.
In a modern airbag press, a pretty gentle press type, most Yarra Valley fruit can be pressed pretty hard and fast without extracting too much hard tannin.
For us in 2017 we had two different ferment types, and, used our tiny basket press.
The whole bunch ferment 2/3 whole bunches and 1/3 destemmed fruit (whole berries) we pressed pretty hard, but, not too fast, then we broke up the press cake that had been formed, reloaded it into the press and went again. Tasting the pressings (wine coming from the press) they were soft, fine and were blended straight back into the free run wine.
By contrast our second ferment of whole berries, we pressed very gently (check out the video above) at about 1/4 of the pressure we used to press the whole bunch fruit and took much longer to press allowing the wine to drain slowly.
Why? Well as we tasting the pressing the seemed firmer, potentially a little harder. From our experience last year we with the same fruit, we were expecting this. Sure, we want to get as much liquid out as possible, it’s worth money! Not, at the cost of buggering up the texture. So we stopped early. Assessing the pressing we had extracted they were a little firmer, at the point where they’d add to the wine rather than detract. So, they were blended straight back in.
We’d probably left 1-2% of the total liquid in the press cake, extracting would have resulted in a coarse hard wine!
Once again there are an infinite number of different machines, techniques that you can use to press wine grapes, it’s just a matter of finding what works for your fruit.