Wine – we all drink it, but how does it get from grape to glass? How is wine made? There is a huge amount of love and effort that goes into producing the wine we drink, and in this guide, we jump right into the process. This post will cover the basics to give you a good idea of how red and white wine is made. It’s not going to go into every single detail but will give you what you need to know to understand it.
How is wine made?
Winemaking has been around for thousands of years. Although it is a relatively natural process, each winemaker will guide the process through various techniques depending on the kind of wine they are producing. Whilst there are relatively consistent steps to this, they will vary.
But as a base level, winemaking usually involves the following steps:
- harvesting,
- crushing and pressing,
- fermentation,
- ageing,
- clarification and
- bottling.
Step 1: Harvesting
The first step is to harvest the grapes. For white wine, grapes are generally white, and for red wine, you use black wine grapes to gain the colour.
It’s important when winemakers harvest the grapes that they do so when the grapes are optimally ripe. If they are underripe they may have too much acidity, and if overripe their alcohol content may be too high. Once grapes are picked, they don’t ripen any further so this is a crucial step. You will also find that some winemakers choose particular times of day to harvest such as harvesting at night in warm climates to ensure that the grapes remain fresh and don’t start fermenting in the barrels!
Step 2: crushing and pressing
Once the grapes are harvested, the grapes go to the winery to be crushed. The winemaker decides whether or not to remove the stems or to ferment grapes as whole clusters (or bunches). Leaving the stems in will add tannin to the wine.
Crushing and pressing is usually performed mechanically these days, although there are still methods like basket press or stomping that are still used today. The grapes are pressed into what is called ‘must’ which is freshly pressed grape juice that contains the skins, seeds and solids.
This step differs depending on whether you are making white, rosé, or orange or red wines. For White wines, fruit is generally crushed and pressed and the juice is quickly removed from contact with the grape skins. However for other wines, the fruit is crushed and left on skin for a given period of time to macerate. This gives the wine colour and tannin structure. The time on skin varies depending on what kind of wine you’re making (rosé won’t be left for very long on skin).
This is the main difference between making red and white wine. For red wine, pressing occurs after fermentation. For white wine, it occurs before. So really Step 2 can occur at different times.
Step 3: fermentation
Fermentation is where the alcohol is made. Yeast either added to the wine or natural yeast on the grapes eats the sugar in the grapes. As it consumes the sugar it creates alcohol and CO2. The CO2 in most wines is allowed to escape, but for Sparkling Wine this is contained so that you get bubbles in the wine.
During the fermentation for red wine, the skins float to the top. This means the juice needs to be stirred to submerge the skin and give the juice more contact with it. Winemakers can either pump wine over the top of the cap, or punch down the cap into the juice. Pumping juice over the cap tends to extract richer flavours, and punching down is usually used for more subtle wines.
Note: Nearly all red wines and some whites undergo secondary fermentation called ‘malolactic fermentation’ to add creaminess, velvety structure and vanilla flavours. This happens after pressing.
Step 4: Ageing
Ageing wine can be done in a variety of storage vessels depending on whether the winemaker wants it to be impacted by the vessel. These include oak barrels, concrete, glass, clay and stainless steel tanks.
Oak barrels impact the most over time, whilst stainless steel impacts the least. The wood oak itself flavours with compounds that smell like vanilla. Concrete and clay tanks soften natural acidity, whilst stainless steel maintains acidity.
The biggest impact on flavour is time. The longer resting time, the more chemical reactions happen to it and change the flavours. White wine is typically aged for less time than red wine which really benefits from this process. It can be aged for several months to several years.
Step 5: clarification
Once the wine has matured it is ready to be ‘fined’. This process usually involves removing unwanted particles that could make it look cloudy or off-colour. The winemaker adds a substance to bind the unwanted particles to make them larger and easy to filter out.
There are many fining agents used in production. Post popular agents include animal products such as milk, egg whites, gelatine and fish guts (seriously). This is where vegan wines will say they are on the label as they use vegan options in fining such as bentonite clay.
While most are fined, there has been a rise of natural, biodynamic and organic wines which don’t always do this. This is why some appear cloudy.
Step 6: Bottling and labeling
After the wine is filtered, it’s time to bottle it. In this step it is important to prevent it from being exposed to oxygen. A small amount of sulphur dioxide is also often added to help with preservation (more on that here).
In summary: how is wine made?
I hope this simple guide has helped shed some light on winemaking. In reality it is a very complicated process with many decision points at every point. But understanding the basics will help you to learn more about the process of what gets into your glass. There is so much love and effort that goes into the winemaking process, and you can see just how much when you understand the ins and outs!