We are still waiting for the French oak influence from the mini staves to kick in.
This can take some months.
pH was 3.7 so added 0.5 g/L H2TA.
This achieved a satisfactory pH of 3.55
The Pinot Noir is a delicate wine showing some varietal character but is, as expected, very light in colour and tannins. Experience has shown us that the influence of the French oak will change this in time.
It is a another waiting game.
The Tempranillo is a great colour with good varietal character and good tannins mainly due I think to our experiment with the Premium Barrique. The French oak influence is just starting to make its presence felt. We need to be careful it does not become "over wooded".
The Semillon yellowing (oxidated polyphenols) continued to increase although flavour was not affected.
So, after much reading and consultation with a local wine maker, I added 0.4 g/L of PVPP.
The winemaker had used this polymer in his Chardonnay and Rose over the years with little detrimental affect.
Polyvinyl-polypyrrolidone was the first synthetic fining agent used in the wine industry coming to Australia in 1972. A well known trade name is Polyclar AT
It is an insoluble high molecular weight polymer and is used in wine as specific absorbent for phenolic compounds which lead to browning and sometimes astringency/bitterness in white wine. Because it is practically insoluble in wine it considered a processing aid rather than an additive.
The powder is mixed into a few litres of wine to disperse it and this is then added to the bulk wine and mixed in thoroughly to ensure good contact between the polymer and the wine.
After a week the wine was racked off the residue which had settled on the bottom of the tank.
The result?
Much lighter in colour but not as much as I expected. Flavour seems to be unaffected by the PVPP process.
I got myself a new wine making 'toy', a filter (see pic above), to 'polish' the white wine and make it brighter.
The filter system has the option of gross, fine and sterile pads.
We drank the Semillon with dinner the other night.
Excellent drop.
When refrigerated however, tartrate crystals (actually potassium bitartrate) precipitated out of the wine and sat on the bottom of the bottle.
Commercial wineries cold stabilize their white wines to overcome this problem by a number of complex processes eg. contact process, filtration, crystal flow or ion exchange.
The problem is purely visual and does not affect the drinking quality of the wine. We won't be cold stabilizing which would be a logistic nightmare. For us it would involve refrigeration at around 0 deg C and then racking the wine off the precipitate.
Our 'customers' will just be made aware of the situation and asked to keep the bottles upright in the fridge 24 hours before consumption.
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