Hi, I’m Chris Pearmund here at the winery at La Grange in Haymarket, Virginia to talk about winemaking for the home winemaker. In this clip, we’re going to talk about turning grapes into grape juice and some few practical matters for a home winemaker.
Basically, there are a couple of different types of wines to make. Red wine, white wine and rose wine. Grape juice as it comes out of the grape is a clear liquid. This clear liquid will ferment to a wine and we measure the sugar in this grape juice. If you wanted to make a white wine, the clear grape liquid coming out would be separated from the grape skins. If you wanted to make a rose juice, the rose juice would come from the skin contact.
This skin phenolic and skin contact will allow some coloration to occur over the course of several hours to start to become a nice pink hue color then the grape solids could be separated from the juice and allow you to make a rose wine.
If you want to make a red wine, the grape skin, the seeds, the pulp inside would ferment with the juice and stay together for a couple of weeks. As the fermentation occurs, the solid particulate matter will dissolve into the wine itself making that texture, the nice red wine phenolic, tannin that you really know in red wine. So, what I’m doing here is basically separating the grapes from the stems. The stems, if you would eat it of course would be very bitter and something you wouldn't want to have as part of your wine process. So by separating all the grapes from the stems, you have something cleaner to work with.
I’m making a bit of a mess here but you kind of get the idea. In a commercial production facility like we have here, we have machines that will do this at the rate of 10 pounds per second. There are also small home winemaker units that separate the stems from the skins. If you were to do then squeeze these whole berries you could do whole berry fermentation but it's not done very often. If you were to squeeze these grapes up as you see, the juice is still very, very clear but it wouldn't take long to have a nice pink rose color and over the course of time, it would become very red.
This is called the refractometer. It will measure the sugar level in the juice. Sugar converts to alcohol at a ratio of about 60%. So basically, 10% sugar would ferment the 6% alcohol, 20% sugar would ferment to about 12% alcohol depending on the yeast strain that you use. In most wine, grape juice would be between 22% to24% sugar fermenting to 13% or 14% alcohol. So, as I put a few drops of juice on this, the light will refract and separate and it will show us that worth 22% sugar, which would ferment to about 12% or 13% alcohol.
Also, we want to process this fruit at a very cold temperature. There is indigenous yeast on the grapes. These yeasts that are here would start to naturally ferment on the skins. To make a nice wine, you want to use controlled yeast rather than indigenous yeast. So, by processing the fruit when it's cold and chilled, you won't have this native yeast doing some work for you that you might not want.
Also, by keeping the fruit very cold, you can extend the time that the skins will be in contact with the juice before fermentation allowing you darker, richer, heavier colors and phenolic and textures in your red wine before you ferment it. If you were to make this out of a white wine, you simply could just have larger volumes of this and pour the juice into your fermentation container.
Obviously, this isn’t going to make a lot of wine for Saturday night parties but I think you’d get the idea. On our next clip, we’re going to talk about turning grape juice into wine and some of the particulars there.
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