Here’s a basic rundown of how red wine is made. We will make it short and sweet.
Grapes are picked and pressed with or without the stems (this is up to the winemaker. Stems can add tannin and depth of flavor) and the whole mess (aka must) often begins the fermentation process in stainless steel or concrete tanks.
This gives the winemaker more control over the temperature and is easier to clean than a barrel, although doing this in a barrel isn’t unheard of.
From here, the winemaker can choose whether to add cultured yeasts (which gives the winemaker more control over how quickly the process goes) or let the wine begin fermentation with ambient yeast in the air (this can take a LONG time and can add a weird flavor).
Fermentation starts. This is where yeast converts the sugar in the juice into alcohol, giving off heat and Carbon Dioxide.
Red wine gets its color from the skins of the grapes. The juice itself does not have color, minus a couple exceptions. This color is further drawn out by heat and alcohol during fermentation.
The must is basically stirred in with the juice, not only extracting more color, but tannin and flavor as well.
When the sugar has converted to alcohol, the yeast dies and fermentation is complete. Winemakers can choose to let the wine rest with the must for a period of time to get any final flavors out before separating and aging the liquid (usually in barrels).
Aging will round out the texture (mouthfeel), flavor, and maturity of a wine. Most parts of the world have aging requirements (for quality control and classification) before allowing a wine to be bottled and sold.
This is also important because it gives sediment and dead yeast cells time to sink to the bottom of the barrel. The clearer wine at the top can then be transferred to a new barrel (this is called racking) for further aging.
This stabilizes a red wine and helps age it by exposing it to oxygen. Some producers do this multiple times, others don’t do it at all.
Another decision! To filter or not to filter. Filtering removes extra particles people may not want to see in their wine, but if it is filtered too finely, flavor could be lost. I don’t personally mind if there are some particles, but if I have to worry about it sticking in my teeth, I’m not super excited.
Bottling. Some countries/wine styles have requirements for aging in the bottle as well (ex: Champagne, Chianti Classico). This final step is where a winemaker decides on the type of closure they’d like… whether it’s cork, screwcap or synthetic cork.
Those are the basics…Of course there are exceptions / different processes / different requirements etc…Remember, we are just here for basics.
Hopefully this was helpful!
