Sorry, I take back (mostly) my earlier comments. I made the mistake of assuming that Nick understood the terms he was using. Fortunately, wiser (and more skeptical) heads prevailed, with better advice.
Nick - just for future reference, there are two terms that have very specific meanings in winemaking, that can often be confusing to newcomers.
"Crush" refers to the process of breaking the skins of the grapes, so that the juices inside are exposed and fermentation can begin. In many cases, the stems are removed at the same time (and by the same machine).
"Press" refers to the process of separating the liquids (juice or wine) from the skins, seeds and other misc. solids. In the case of white wines, this is often done right after "crush", so that the fermentation process is started on the juice only. In the case of red wines, "press" usually happens AFTER fermentation, as you want to ferment on the skins to get the colors and tannins from the skins into the wine.
So what you had was 30 gallons of crushed grapes, or must. Strictly speaking, it was not "pressed juice". Fortunately for you, crushed grapes is what you want in this instance, as you want that skin contact during fermentation. Joe's advice above was right on. If you follow those recommendations, you should end up with 18 to 20 gallons of very nice Sangiovese.
Happy fermenting --
Doug