is there a proper way to use fresh grape juice (i.e. Merlot) to condition a wine?
I thought to “cook” it under 80 degrees Celsius, cool down, mix into wine with Potassium Sorbate. This is instead of using sugar.
I don't think I would cook it. I would be afraid it might give it a "cooked" flavor. I'm guessing this is already pressed and cleared and could potentially be consumed as is?? I'd probably add Potassium Sorbate and Potassium Metabisulphite and just us it as is.
I read that if slow cooker is used with temperature below 70 degrees, it will not affect flavor and will allow to increase sugar content.
Also it seems that pressure canner allows to make juice concentrate without loosing its flavor.
I want to try both today to see how it goes...
You don't have to go so high in temperature if you hold the juice at temperature for a while. For example, if you hold meat at 55C for ~90 minutes, it is safe to eat.