Thursday, March 31, 2011

An Autumn Morning at the Beach

The strange weather continues. A few days fine, a few days raining. It looked quite threatening with dark skies on Wednesday but we headed down to the beach for a swim and a walk.
However the ocean was very rough so a swim was out.
Everyone else must have thought it was a non beach day as there was only us plus a few seagulls.

That afternoon there was bright sunshine, blue skies and temperatures around 30 deg C!
So much for the weather bureau's forecast of cool and cloudy.

Monday, March 21, 2011

Autumn Flowers

In celebration of the Autumn Equinox, here are some flowers currently blooming in our garden.

Sunday, March 20, 2011

Malolactic Fermentation (MLF)

Grape juice and the resultant wine contains quite a number of acids, the main ones being malic and tartaric.
The amount of acid in a wine is known as titratable acid (TA) and the acid strength is known as pH. Acid is an important component of wine contributing to taste (balance) as well as the chemical reactions that take place during the wine making process both natural and winemaker induced.
Malic acid is very tart and somewhat unstable in wine.
To improve the acid taste and increase the stability of wine it is prudent to convert this malic acid into the softer and more stable lactic acid, particularly in red wine.
This is done by introducing lactic acid bacteria (LAB) either as a culture or by natural means from the bacteria already present in the winery.
We use an Oenococcus oeni culture which is added to the fermenting must.

These little fellas (the white ones) get to work 'consuming' the malic acid and turning it into lactic acid and carbon dioxide. The evolution of this gas is the reason the process is called a 'fermentation'.
Improved wine stability comes about from not letting this process happen when the wine is in the bottle with obvious dire results ie. blown out corks and shattered glass.
MLF however will not take place in the presence of sulphur dioxide which is added to wine as an antioxidant and antibacterial agent. You see this as 'Preservative (220) Added' written on a wine label. This means we have to leave the wine unprotected until the MLF process is complete.
This is always a bit of a nail biting time in a simple Vin de Garage winery so this is the reason we add a culture ie. to get the process going and finished as quickly as possible.
The only sure way to detect if MLF has occurred is with a paper-chromatographic test.
In the meantime Vintage 2011 continues with the Semillon racked off the fermentation lees (dead yeast cells) and bentonite (clay used for stabilization and clarifying) residue and sulphuring. Now we just wait until all the remaining solids settle out and the wine clarifies. This may necessitate another racking or two plus sulphur additions.
The Tempranillo has gone through MLF and has been racked off the fermentation lees, sulphured and egg white added to begin the clarification process.
We are waiting for the Pinot Noir to complete MLF.
It continues to rain and rain. So far the Cabernet Sauvignon is holding up but experience has shown that a 'collapse' of bunches can occur virtually overnight eg. splitting.
So we are ready to pick at a moment's notice. It could be we are forced to make Rose' from this grape variety this year.
Only time will tell.

Monday, March 14, 2011

Vintage 2011 Continues

We have picked the Pinot Noir which came in at 13.5 Baume and pH 3.5
There were small patches of botrytis which were easily handled so it was not a bad result for a difficult year.
I am trying a new red wine yeast this year. It is an Italian strain of Saccharomyces cerevisiae and was supposed to be a fast fermenter that brings out the flavour of red grapes.
It worked well on the Tempranillo and is fermenting the Pinot Noir quickly too.
The ferment gets quite hot, around (30+deg C), which helps extract plenty of colour from the skins. Light coloured Pinots are always an inherent problem. But to prevent it getting too hot meant punching down the cap (mixing the skins that float to the top of the fermenting wine, due to the carbon dioxide being released, back into it) a few more times a day than normal including a late one just before bed and an early one before breakfast. I will let it sit a while in the sealed tank after fermentation finishes in an effort to extract more colour.
The malolactic fermentation culture and oak chips have already been added to the wine at this stage.
I have always used a wine yeast culture for fermenting wines ie. commercial strains of Saccharomyces cerevisiae.

This yeast quickly dominates the fermentation while repressing wild yeasts. This ensures a reliable and predictable fermentation.
However different S. cerevisiae yeast strains can have differing physiological and fermentative properties. This means the actual strain of yeast selected can have a direct impact on the finished wine so it's good to try different ones.
Yeasts are normally already present on grape skins ie. the grey bloom. Fermentation can be done with these endogenous "wild yeasts", but this procedure can give unpredictable results, which depend upon the exact types of yeast species present.
A lot of wine makers experiment with wild yeast fermentation. They are said to produce atypical flavour profiles and/or increased complexity in wines. With my relatively primitive production set up there would be a risk of wine spoilage using this method.
But one day it might be one worth taking.

Thursday, March 10, 2011

Vintage Helpers

During harvest four hands are always better than two.
The co driver is now an expert picker and all round cellar hand.
No longer does she complain about being covered in spiders and bugs as she makes her way down the rows snipping off bunches and quickly filling buckets.
And she is a deft bucket handler and stalk remover at the crusher/destemmer too.

The clean up process after crushing is very important. Getting rid of the residue of stalks and spilled grapes stops the usual invasion of annoying vinegar flies and helps prevent the development of wild yeasts within the winery area.
Cleaning the equipment to be ready for the next crush is similarly important.
I usually do this in the backyard. There is always a pile of grapes washed out of the crusher.
My cleaning staff of bower birds and currawongs is always waiting in the surrounding trees and at the ready to make short work of those. After all, the netting has been preventing them getting to the ripening grapes for weeks.
But this morning we had a new member of staff at work. Life in the country is great.

Tuesday, March 08, 2011

Vintage 2011 Begins

With the weather still not cooperating and forecasts predicting a wetter than normal Autumn under the influence of La Nina, we bit the bullet and started harvest.
First off was the Tempranillo. Fruit quality was down on previous years as was yield.
Sugar level was 12.5 degrees Baume' and pH 3.5.
Under the circumstances we were not too disappointed. A higher Be' (with a resultant higher final wine alcohol level) would have been nice however.

The Semillon came in at 11.5 Be' which is acceptable for wines made from this variety of white grape. The pH was 3.4
The fruit has been affected by botrytis much of which we managed to manually sort through and discard. It will be interesting to see if that fungus has any affect on the resultant wine quality particularly its oxidation 'resistance'.
Anyway, both are currently fermenting away and there is the usual fragrant smell wafting around the house.
Next we will be turning our attention to the Pinot Noir.
The Cabernet Sauvignon has a long way to go as yet.