Steps #14-17: Extended Maceration to Press

Here is the detail process chart:

Process chart S14-18.png


Step #16: Extended Maceration

On completion of Primary Fermentation, we can consider extending the maceration to further extract Tannins and increase the level of Bound Anthocyanins. Because the alcohol level is now high, Extended Maceration will extract relatively more seed tannins which can be beneficial if seeds were very ripe and the addition of nutty/almondy taste is desired. We keep the temperature at 70 °F and continue with 1 punch-down per day for up to 5 days (depending on taste).

The Extended Maceration punch-down process is:

  • Take the tank cover off.

  • Punch down the must while making sure not to crush seeds at the bottom of the tank.

  • Take two 2mL samples for chemical analysis.

  • Taste sample and decide whether to continue or end extended maceration.

  • Wipe down the walls of the tank with disinfectant (KMBS solution), cover the must with a new blanket of Argon or CO2 and put the tank cover back on

Steps #14-15 & 17 Pressing Decisions

Pressing is initiated when

  • Primary Fermentation (step #13) was incomplete when Tannin levels reached 2000 or 110% on previous Anthocyanin peak, or

  • Primary Fermentation (step #13) was completed in the fermentation tank, and tannin levels were high enough to skip extended maceration, or

  • the must had been subjected to extended maceration, and that is complete (step 16)

If pressing is initiated before Primary Fermentation is complete, we press the cap only: we scoop the cap out of the fermentation tank into the press, then press and return the pressed juice to the fermentation tank where the primary fermentation is completed.

The side-by-side pictures show the two alternatives. When we press the entire must (when the primary fermentation was completed), we first drain the juice through a thieve into the press and then move the must over a steel channel into the press. When we press the cap only, we scoop out the cap into 5-gallon buckets, empty the buckets into the press, press and return the pressed juice to the fermentation tank by buckets.


We use a 1.5-ton bladder press: Bucher Vaslin XPro 5 ( which, we now realise, is overkill for our requirements. We extract the additionally required juice at very low pressure (0.2 to 0.3 bar only) from the must in multiple rounds. This is called the Press-Run. The remaining pressed must (now called pomace) is scooped out and distributed in the vineyard as fertiliser for the next season.

small presses.jpg

For small fermentation batches, we don’t use the big bladder press. Instead, we use a small manual press which saves in setup and cleaning efforts. There are two types. In modern manual bladder presses, water pressure fills a bladder which presses the must outside against a stainless steel sieve. In old-fashioned screw presses, a wood lid is pressed down by a big screw, and the juice escapes laterally through a vertical wood lattice. We have used both types for the small lots from the upper vineyard. The picture on the right shows the two types.

Finishing Primary Fermentation

If the fermentation was not completed before pressing due to high tannin extraction during Phase 2 of the Primary Fermentation, then the fermentation now needs to be completed either in the barrels and the variable-top steel tank or the fermentation tank. The process is:

  • Take test samples, stir and then recover with Argon blanket

  • Taste and measure (OenoFoss & WineXray)

  • Keep temperature at 70 °F and continue the daily process until Brix reaches -1.5.

If the fermentation is finished in the barrels, then the barrels need to be heated, and the temperature kept at around 70 degrees. This is accomplished with heating mats built into the barrel dollies.


The juice from pressing is held for a few days to a few weeks in steel tanks to let dead yeast cells and other solid material sink to the bottom as sediment before we syphon the clear young wine off to barrels or topup tanks for cellaring. We use this racking step also to mix juice from different fermentations and press-runs. We protect the young wine in the settlement tanks with an Argon gas cover to prevent oxidation and growth of microbes on the surface.


Data Management

Data Management for Steps 14 to 16 is identical to Step 13. For the final press and the allocation to barrels and topup tanks (i.e. Cellar Batches) we need to first define the batches and then specify the allocation of fermentation batches to each new cellar batch. This is done in the “ALL: CellarBatchComposition” – layout. The picture shows a screenshot of the layout for the 18CSMeCFPV1 cellar batch

Tracking Results 2018

In 2018 we made the following decisions:

  • We did not press any of the fermentations early, nor did we extend the maceration periods after the fermentations were complete. The tannin and anthocyanin levels were adequate without.

  • We pressed the two Merlot - Cabernet Franc ferments in the old-fashioned manual screw press and combined the juice for settlement into a single stainless steel barrel.

  • We pressed the Cabernet Sauvignon ferment in the large bladder press and settled the juice in the large Settling Tank

  • We free-flowed the Petit Verdot ferment into two glass carboys for settlement.

  • Finally, we mixed, at varying ratios, the different settlement tanks into 3 French barrels (one new, two neutral) and five topup tanks. The goal was to get one barrel of 100% Cabernet Sauvignon, two barrels of different Bordeaux-style mixes and separate topup tanks which reflect these mixes.

The following spreadsheet shows the allocations to barrels (green) and topup tanks (white):

allocation to barrels.png


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Last updated: November 12, 2018