Wednesday, February 13, 2008

From Plant to Bottle: Harvest – A Winemaker’s Crush

This is part 5 of the From Plant to Bottle series.  If you are just joining me, you may want to start from the beginning of this series.

The grapes have now been harvested and are brought to the winery for crushing and pressing or just crushing, depending on what you are making.  If we are making a white wine such as Sauvignon Blanc, the grapes will be crushed and pressed in the same session because you only ferment the juice.  Red wines are fermented on the skins, which is where the wine gets its red color, and so are pressed at a later time.  I’ll start with the processing of a white wine.

One of the nice things about moving to the professional winemaking world from the amateur world is all the great toys wineries have.  We have a wonderful machine called a de-stemmer crusher.  I find it one of the most fascinating pieces of equipment and offer my compliments to whomever invented it.  It seems like a rather simple machine. The inner workings consist of a rotating stainless steel drum, into which holes have been punched….reminds me of Swiss cheese.  There is an augur inside the drum with paddles on the shaft.  On the underneath are two adjustable rollers for crushing the grapes as they fall through.  They can be moved closer together for a finer crushing or further apart for a light crushing.  How the grapes are crushed can define the style of wine made from those grapes.  Very tight crushing can extract some astringency from the grape skins in certain varieties which may be unwanted in the finished wine and so one can opt to open the rollers more than usual.  Also, for reds, one might want a fruitier style and leave grapes mostly whole so that fermentation can take place inside the grapes…this is a whole different subject and will be discussed at another time.  As the grapes are dumped into the hopper above, the auger feeds them through the drum.  The drum removes the grapes from the stems and the grapes fall down through the roller.  The stems come out the side of the machine, mostly intact with nary a grape left on them.  I have always been amazed to see how neat and clean this operation is, quite an interesting production.  The crushed grapes fall into what is called a must pump (remember the term “must” is what we call the crushed product or juice about to become wine).  This pump has a large hose (in our case 3 inches in diameter) through which the grapes are pumped into the press.

I would like to point out that the second most asked question at the winery (after how did I become a winemaker) is “you mean you don’t do it like Lucy?”  It seems every person on the planet has seen that Lucille Ball clip.  Then they want to see my feet.  I assure you they are not purple.

Our press is what is called a bladder press, and is another fabulous toy.  It looks like a large slotted cylinder lying on its side and as it rotates juice drains into a large pan stationed below it.  The grapes are fed through what is called the axial feed, which is a wide pipe sticking out of the end of the cylinder.  The press is computer operated with a built in compressor.  While we are pumping the must into the press, it is set on “manual” where it simply makes the drum turn and de-juices the grapes while the press is being filled.  In the meantime this juice from the pan is being pumped into the fermentation tank with yet another pump.  After the press is full, the axial feed is closed off and the press is started on one of the pre-set programs.  There is a liner inside the press that gets filled up with air a little at a time exerting pressure on the must as it expands (hence the “bladder” press).  The program actually goes through a fairly complex process of pressing, backing off, rotating around, and then pressing some more.  It takes about one and one-half hours to do a complete press.  The process must go slowly like this because, if it tried to squeeze it all at once, the grapes would just slide around and it would not be a complete pressing.  When the pressing session is done, the pan is removed from underneath and a large bin is place under the press.  The sliding doors of the press are opened and the drum is turned on “manual” dropping the skins and seeds into the bin.  At this point, even though it was a very gentle pressing, what is left is as dry as granola.  You can run your hands through it and not get them wet.  The bin full of skins and seeds is then dumped into a truck to be taken out on the farm and get composted back into the earth.

It takes a little practice with your new press to figure out when it is just about full.  Early on at our winery, I had someone helping me so she could get some hands-on experience and learn winemaking.  She was monitoring the press while it was filling and was alone with it in the lower level of the winery, while the rest of us were outside on the upper level doing the processing.  All of a sudden, we hear this horrendous alarm and we go running into the winery to find Debbie covered with grape juice as it was spraying out of the slits of the press drum.  It was quite a mess, covering her, the walls and the floor.  Worse, there is not way to stop it until the pressure that built up in the drum dies down.  This also falls under the category of “dirty jobs”.  Fortunately, we have over 30 foot ceilings, so we didn’t have to clean them too!  We still laugh about this but we did learn something.  We now know exactly how many chardonnay grapes our press will hold.  And Debbie has gone on to be a very successful winemaker with a winery of her own.

1 comment:

  1. How to remedy wine faults with sulpher like smells at 3 stages of development:
    1. H2s rotten egg smell
    2. Mercapton-- use of copper and how much
    3. Dimercapton--use of absorbic acid--how much--use of copper--how much--use of fining and or yeast and how much per gal.
    Next-- How to measure acidity in a fermenting wine?
    Sincerly and thanks,