The pressing process

Free Run

When the maker decides it’s time to press, they firstly separate the liquid portion of the wine from the skins, seeds and potentially stalks in the fermenter.

Depending on the fermenter that can be done by draining it off and pumping it into a tank or pumping it via a strainer.

That liquid is called the free run. This is typically around 600L per tonne.

The wet solids are then transferred to a press. Assuming we’re producing a wine of substance that typically means either a basket press or an airbag press.

There’s still about 120-180L per tonne liquid left in the solids. The practical way to get this out is to use a press. Being simple folk we just call this fraction the pressings!

Pressing

The wet solids are then transferred to a press. Assuming we’re producing a wine of substance that typically means either a basket press or an airbag press.

Bucketing the skins seeds and last drops of wine from a fermenter into a basket press

They can be separated into as few or as many fractions as you want. Typically done by standing at the press tasting liquids coming out.

Now comes a truckload of variables. Initially, it’s all about time and pressure. With very little pressure and in quick time most of the remaining liquid will be separated by the press.

This first fraction is typically blended straight into the free run.

As the pressing process continues more pressure and time are required to squeeze out the remaining liquid.

This is where experience with fruit from the region, variety, specific vineyard and vintage conditions comes to play.

Basket presses and airbag presses are overall very gentle.

The risk of pressing too fast and hard is that you extract tougher and potentially bitter tannins. Even though this pressings fraction may be as little as 1-5% of the wine it can have a significant impact.

Some parcels can be pressed as hard and fast as you like and all the pressings blended straight back into the bulk of the wine. Most Yarra Valley fruit sits in this category.

When Dominique Portet started making wine from Yarra fruit he pressed like it was fruit from the Pyrenees, taking it very slowly. Pressing too fast in the Pyrenees gives hard tannin.

Historically regions like McLaren Vale would separate pressings and free run as a default.

The quality of the pressings like anything to do with wine will be, in large, dependent on the quality of the fruit, combined with the skill of the maker in extracting tannins during fermentation and then the pressing process.

There is a soup of tannins in wine and the amount of these tannins will vary from year to year. Giovanni Angeli from Massolino analyses tannins and phenolic compounds in fruit and wine every year. As an example, he saw near twice the dry extract (a measure of these compounds) in 2006 when the stress on the vines pushed them to produce more tannins to ripen seeds as they strive to reproduce for survival.

I don’t know the full details of Wendouree’s fermentation techniques for 2017 or their pressing. They use open fermenters and a basket press and tend to press once then tip the press cake into another press cage to break it up to be pressed a final time.

I don’t know what fraction(s) go into the pressings.

In the video below we run through the process of pressing the 2016 Wine Decoded Shiraz, from separating the free run to pressing the still wet skins. We pressed the 2016 harder than the 2017, demonstating that you have to adjust to each vintage and always TASTE! You can read the full article “Pressing Time!” Wine Decoded Shiraz Vintage 16 Episode 08” here.

In the video below, from the 2017 Bathtub Winemaking Project we explore the pressing component of making our Shiraz. You can read the full article “Pressing Time – The Shiraz is Heading out of the Bathtub & Into the Basket Press – Bathtub Winemaking Project Day 14” here.

The video below illustrates shows a red ferment in Bordeaux in tank and the separation of free-run and pressings.

The Taste of Pressings

The taste of pressings has a lot to do with their chemistry. Pressings tend to have a higher pH and lower acidity, before acid is added if any at all, with more dry extract or tannin. This has a major impact on mouthfeel and texture. They can also have less obvious varietal character.

If the quality of the fruit is high, a tick for Wendouree, pressing will still have a solid backbone of fruit. When bottled separately like Wendouree’s the wine tends to have greater depth of tannin and more secondary, for example, earthy characters and less fruity characters compared to the free run.

When the fruit is not of quality, the ferments have been managed aggressively and the pressing process has been hard and fast, the pressings fraction tends to be thin with harsh tannins.

Tannin precursors come from the old wood in the root system, trunk and head of the vine. Old vines typically have a great volume of these vine parts meaning more potential tannin in the fruit. Lower yields result in more possible tannin being available per bunch. A long slow season allows for more accumulation of these compounds in the fruit.

Wendouree ticks the box for all of these factors in 2017.

Wendouree has moved towards more approachable mouthfeel from the early 00’s through to today.

It’ll be interesting to see how the pressings wine compares to the other 2017’s from Wendouree.

In 2016 we had a warm, fast vintage in the Yarra, our fruit had less tannin and we pressed reasonably hard.

In 2017 we had a long cool season, all be it with a slightly better parcel of fruit from the vineyards, we had insane colour and tannin and pressed very gently.

You can see a video of the pressing of our 2017 exploring many of the above factors in this article.

That’s about the best I can do without writing that book!

 

 

 

 

If you’ve got any questions, drop us a line in the comments and we'll get back to you.

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