Once the grapes are in the lagar, the process for making Port wine in our lagares at Graham’s Quinta dos Malvedos goes like this:
- Tread the grapes, usually for four hours, possibly more or less at Henry’s discretion. Treading is important not only to break up the grapes to release their juice, but to massage the skins against the floor of the lagar in an effort to extract the colour and flavour compounds which are held in the skin of the grape.
- Fermentation, the process by which yeasts act to consume sugars, create alcohol and turn grape juice (known as must in the context of winemaking) into wine, begins and a cap forms as the skins and pips rise to the top and the must settles to the bottom of the lagar.
- Periodically, Henry will set the lagar to perform the cap plunging*. This is a process by which the cap is broken up and plunged back into and mixed again with the must. This process is important to continue extracting the maximum possible colour and flavour from the skins.
- We monitor the baumé, the measure of sugar in the must, regularly. To make Port, we want to stop the fermentation at a time when there is still a high quantity of sugars – roughly half way through the fermentation. Typically we have around 48 hours from the start of treading until the time we need to arrest fermentation.
- When the time comes, we run off the must from the lagar into a tank where the wine is mixed with aguardente, a colourless and flavourless pure grape spirit of 77% alcohol. The addition of this alcohol kills the remaining yeasts and stops the fermentation process.
We now have Port wine, just a few minutes old!
Over the coming weeks of Harvest we will try to capture each of these steps on video for you. Here, you can watch the remontage process being performed on our very first lagar of the Harvest, Tinta Barroca. Henry and Charles are pleased with the colour extraction so far, and it will only get better!
* Jamie Goode kindly corrected me, this is not remontage, but in fact what the French call pigeage, and the Portuguese call plunging the cap.