Wednesday, February 5, 2014

Crush and ferment - winemaking Step 2

So on Sunday we picked the first grapes from our vineyard for quite a long time. Hooray. But that was only the start of the work.

Now on to the winemaking.

But first we need to step back a bit. How did we know when was the right time to pick. It is not possible to judge by look, but taste gives a good indicator. We knew that we would be close, and checking the sugar content, or baume, of our grapes confirmed that they were ripe for picking. Using a hydrometer, the baume measured 13, which was exactly smack bang in the middle of the ideal reading of between 12 and 14. No need to doctor with sugar (not that we would ever do that!)

Having picked, we then sprinkled 8-10 grams of sodium metabisulphite per 100litres of grapes just prior to crushing. This kills the natural yeasts on the grapes. Some home winemakers skip this step and let natural yeasts do the work. Unfortunately, you have no idea as to how much natural yeast there is, so this method is a bit unpredictable. If you have ever had dodgy homemade wine, this is probably why.

We crushed using our combined crusher/destemmer.

If I had $5 from everyone who has ever asked me whether we crush our grapes with our feet, I'd be buying bottles of Grange! If you are only dealing with a few kilos of grapes, you probably could. After all, the aim of crushing is simply to break the skins so that the yeasts can start their work of converting sugar to alcohol. If you have more than a few kilos, it's easier to use machinery, believe me!

Once crushed we transferred the grapes, skins and all (now called the must) into a food grade plastic drum with a lid. For the first 24 hours or so after crushing, the sodium metabisulphite will continue killing off the natural yeasts. Then you re-introduce yeast. Yes, sounds crazy. The must is inoculated with red winemaking yeasts and yeast nutrients (from a winemaking supplier), according to their directions.

Hopefully, fermentation soon starts at this point. Weird bubbling sounds come out of the drum.

For the last few days, our job has been to regularly punch down the skins that rise to the top so they don't dry out. We also tested for acidity, which should be between 3.3 and 3.4. Our must was a bit too acid, so we added calcium carbonate, and now all is well.

The other thing to monitor is that the wine does not get too warm, which means simply dropping ice bricks into the must, and regularly changing them. You don't want the must to be warmer than 30C. Fortunately, this hasn't been a big issue this week here. We've had a merciful respite from the heat, with nice temps in the low 20s. For once, mother nature is with us in our winemaking.

So that's it for the moment. Next stop...pressing.

Just for interest, here is what our winemaking central looks like:

So here it is. The wine is fermenting in the blue drum at left. If you are wondering what a microwave oven has to do with winemaking, the answer is nothing.
There are a number of commercial wineries around here and it was interesting to read a news report in the local paper about the picking. They noted that this year has been great for grape quality in the area, although quantity isn't massive. Just as we found. It was disappointing to note that the biggest winery here has bought a mechanical harvester. And there goes a few more jobs in this high unemployment area. But I won't go there here!

If you have any questions, please don't hesitate to ask in the comments. Me and Action Man will do our best to answer them.


JohnandJean said...

Did you combine the Shiraz and Chambourcin or was this only one of the varieties?
Which yeast did you use?

Paola said...

This wine is a blend of Shiraz, Chambourcin and Merlot.
The yeast used is itES10 from Everintec (an Italian company). We also used this to make Cabernet Sauvignon. This is the best yeast we have found.