Thursday, February 27, 2014

State Forest Logging

We are surrounded by state forests and national parks.
We have been hearing a lot of noise to the north of us lately.
Our neighbours up that way said the state forest had been logging right up to their boundary fence.
There are some beautiful big trees eg. spotted gum, in that area as well as some pristine temperate rainforest gullies.
So we went for a look at what was happening by driving along the major fire trail that does a big loop from our highway.
It is in places still quite beautiful and untouched.

But the timber felling operation currently underway is very obvious,
But I guess that's what state forests are for.

Rumour has it that once this is finished the area will be handed over to National Parks and become part of Meroo National Park.
This has been the scenario on other occasions.
And talking of big trees, there is one just to the south of us that had been left by the loggers (who knows why) and is now protected by National Parks.
Known as 'old spotty' or 'old blotchy', depending on whom you talk to, it is a spotted gum (Corymbia maculata) with some impressive statistics.
Circumference: 10.8m (423 in)
Height: 50.0m (193ft)
Crown: 30.0m (98ft)
Check out some pictures here.

Tuesday, February 25, 2014

Wine Tanks

Continuing with the wine making equipment theme, the last essential piece in our operation is the variable capacity stainless steel tank.
We have four: 2 x 100L and 2 x 200L.
They are Italian (which seems to be the source of a lot of good small winemaking equipment) and made from 304 stainless steel.
The variable capacity feature is enabled by a floating lid which sits and is sealed on the wine surface thus excluding any air during storage.

The floating lid has an integrated airlock and a wide rim to accommodate an inflatable bladder.

The bladder is inflated by a hand pump which has a pressure gauge to help avoid over inflation.

Bladder inflated

Sunday, February 23, 2014

Vintage 2014 Continues / Part 3

The Semillon finished fermenting and we added bentonite to begin the clarification and stabilisation process ie. protein removal.
Bentonite is a clay, impure hydrated aluminium silicate, and is found only in a few places in the world. The most suitable for wine comes from Montana and Wyoming.
The clay (around 0.5g/L of wine ) is hydrated in approximately 5 times its weight in hot water and left to swell for 12 to 24 hours. By that time it forms a thick thixotropic paste.

A little wine is gradually added to the paste to form a slurry which is then added into the Semillon and mixed thoroughly.
This addition has the affect of the bentonite adsorbing the proteins in the wine by either by electrostatic  attraction or by hydrogen bonding. Bentonite is negatively charged, the wine protein positively. This is another case where chemical addition activity is dependant on wine pH. The lower the pH the more positive is the protein molecule charge.
While the initial muddy look of the wine can be a bit disconcerting to the uninitiated, in a few weeks we will be able to rack the clarified wine off the settled residue layer.

The Pinot Noir came in at 11.3 deg Baume and pH 3.4 after a full block test on 17th February ie. not ripe.
This was a bit of a surprise as it has not 'progressed' too far from a few weeks ago. Maybe the 50mm of rain had more of a dilution affect than expected. So it is still a waiting game.
As expected a quick test of the Cabernet resulted in 10.0 deg Baume.
The Tempranillo needs another week or so before its first racking ie. siphoning the clear wine off the solid residue that will have formed on the bottom of the tank after the egg white fining addition.
And just when you think you have all the pests covered, I found around 5 satin bower birds in the Cabernet. As the vines are completely enclosed in netting I went looking for a hole and found at least 6 right on the bottom of the net where it is pegged into the ground. Satin bower birds, our major bird pest, are very cunning and will walk around the base of the netting looking for a way in. I have even seen them trying to lift the netting with their heads in an attempt to get entry.

Our other bird pest, the currawong usually clambers over the top and sides. It has a long beak and can swing back and forth on the nets and take a peck at a bunch on the inward cycle.
A little further investigation found that these holes are being made by rabbits (scrapings and poo evident ) who must be anxious to get at the fresh green grass shoots of the mid rows and are chewing their way through the nets. We are now baiting the area.

Friday, February 21, 2014

The Wine Press

In previous posts we have mentioned and had pictures of our wine press.

There are many designs for wine presses but the object for all styles is the same ie. to extract juice from crushed grapes (the must) or sometimes whole uncrushed bunches.
The press exerts controlled pressure in order to free the juice from the grapes. The pressure must be controlled in order to avoid crushing the seeds and any remaining stalks which releases undesirable phenolics into the wine.
We have a simple manual basket press which is probably the most recognizable piece of wine equipment. It's basic design has not changed in nearly 10 centuries.

A basket press consists of a large slatted basket which is filled with the crushed grapes.
The basket consists of two halves which are locked together with pins

Pressure is applied through a plate that is forced down onto the fruit. In some cases, when grape volume is low, we need to add blocks on top of the plate to apply the necessary pressure.

The mechanism to lower the plate onto the grapes is a manually operated screw. A long handle inserted into a slot in the screw (on the right) enables more pressure to be exerted. More sophisticated and larger basket presses are hydraulic.

The juice flows through openings in the basket leaving the skins, seeds and stalks (the marc) behind.
For red wine considerable pressure is used to extract as much skin tannin (within reason) and colour as possible.
The marc can be virtually dry when pressing is finished. Many wineries separate free run and pressings to be blended later. We have never seen the need for that here and return the pressings immediately to the free run.

For white wine less pressure is used as we try to avoid skin tannins being introduced into the wine and concentrate on getting as much free run juice out of the must as possible. There requires constant tasting of the juice flowing from the press. The decision to stop is always subjective.
The picture above shows the difference in height of the marc remaining after pressing both Tempranillo and Semillon although the initial amount of must was approximately the same. 
Luckily with our operation being non commercial we can err on the side of caution not having to worry about yield and economics, just quality.

Wednesday, February 19, 2014

The Crusher Destemmer

A necessary piece of equipment in any winery is a crusher/ destemmer. The grapes need to be crushed to extract the juice and the stems removed to prevent phenolics contained in them contaminating the wine.
Ours is a very basic manual model. The grape bunches are fed into the hopper on top and then pass through rollers where the berries are crushed and fall onto a stainless steel screen. There the stems are removed by beaters and the berries and juice  fall through the screen while the stems are ejected.
Below is the hopper with the rollers at the bottom. The 'paddles' on top rotate and distribute the bunches evenly across the rollers and push them down onto them..

From underneath the crusher you can see the beaters which rotate above the screen (removed for this pic) and destem the crushed grapes. The beater axle is set at an angle which allows the movement of  the bunches along the screen, where the grapes all eventually fall through. The now bare stems are ejected through the large hole at the end (top of pic).

Above is the stainless steel screen removed from the crusher.

The crusher with the stainless steel screen in place.

Monday, February 17, 2014

Vintage 2014 Continues / Part 2

The Tempranillo finished fermenting on 13th February. We test the status of the ferment by use of a hydrometer. This measures the density of a liquid so when it reads 1.0 we know that the solution is basically sugar free ie. the yeast has consumed it all and turned it into alcohol (plus CO2).
C6H12O6 + yeast → 2 C2H5OH + 2 CO2
The grape juice is now wine.
On 14th February we drained the wine through the press and then pressed the skins thoroughly adding the pressings back into the free run wine. The wine was stored in a stainless steel tank where 50mg/L SO2 was added. To exclude air contact, the tank is sealed with a floating lid held firm by an inflatable bladder.

The marc was then returned to the vineyard rows. The skins are rich in potassium and are a good source of fertilizer for that element as well as a soil conditioner.

A further pH test was performed and confirmed at 3.8.
We wanted to adjust it to 3.6.
To achieve this tartaric acid (a natural grape acid) is added to the wine.
There is no magic formula ie. add x grams H2TA to xx litres wine to reduce pH by 0.1 units due to the differing buffering capacity of different wines.
It is a matter of trial and error. And it has to be done gradually as deacidfication caused by too much H2TA is a pain.
So our initial addition was 1.0 g/L.
This resulted in a pH of 3.7 so we added another 0.5g/L which got us to 3.6.
To clarify the wine we use egg white. One white is slowly mixed into a 10% solution with water and 0.5% salt to help dissolve the protein. This is then thoroughly mixed into the wine. Within a few weeks the solids suspended in the wine will settle to the bottom of the tank and the clear liquid on top will be racked off.
We do not use oak barrels for storage and aging. Previously we have added oak mini staves to our red wine in order to impart an oak nose and flavour. This vintage we are trying out a powdered tannin product made from oak heartwood and gall. This addition is said to produce exactly the same oak characteristics to those extracted when aging wine in wooden barrels.

Meanwhile the Semillon is still fermenting. Ferment temperature is around 25 deg C which is a little too high for good quality white wine but as mentioned before there is nothing much we can do about that.
Suffice to say that the smell of the ferment in the 'winery' is wonderful.
Our last test showed that it is about 50% 'there'.
The rain event mentioned in the last post lasted for 3 days and dropped around 50 mm on us.
So that was pretty much the forecast.
The farmers out west got 50-100mm in places so that was good for them. They still need a lot more however.
Our next jobs are to sulphur and fine the Semillon after fermentation is finished and test the Pinot Noir to establish whether harvest is imminent.
We will now need to spray the Cabernet and maybe the Pinot depending on its condition after the rain.

Friday, February 14, 2014

Vintage 2014 Continues / Part 1

We picked the Semillon on 11th February.
 "Annebelle" again pitched in to help. It was a relatively cool day (20 deg C) with just a hint of very light drizzle at times so the working conditions were pleasant plus the grapes were not getting too hot. Low temperature fermentation is a prerequisite for good white wine. In our vin de garage winery environment where refrigeration is out of the question ambient conditions are important. However we will never reach the preferred 10-16 deg C range for whites during our summer.
The grapes were in excellent condition. The small amount of botrytis that had broken out had been stopped in its tracks by the long hot dry summer and the affected berries had shriveled to the point of being inconsequential for good wine production.

Sugar level was 12.5 deg Baume and pH 3.2. Absolutely no complaints about that.
The grapes were immediately crushed and destemmed. We continually added a combination of sulphur dioxide (50mg/L) and ascorbic acid (50mg/L) at the crusher to prevent juice oxidation.
Sulphur dioxide (SO2) is produced by adding potassium metabisulphite (KMS) to water. 1.0g of KMS produces approximately 0.5g of SO2.
To the resultant must (juice + skins) we added a pectin splitting enzyme to increase the yield of drained juice.
The must was then drained through the press and the skins very lightly pressed. Free run juice makes the best white wine. Over pressed whites tend to absorb the phenolics and tannins present in the skins and any residual stalks and reduce the quality of the wine.
More SO2 (25mg/L) was added at the press.
The juice was then transferred to a stainless steel tank and DAP (fermentation accelerator) and a rehydrated white wine specific yeast added.
Draining the Semillon

Fermentation took 36 hours to start. The addition of SO2 in the initial stages of production inhibits the onset of fermentation so it always takes longer to start than red wine. This lag is a bit of a critical time for vin de garage wineries with the juice exposed to oxidation, hence our care with the correct additions of SO2 / ascorbic acid at the appropriate times.
Proper wineries employ reductive oenology ie. preventing juice and wine being exposed to air eg. use of CO2, combined with effective temperature control.
The Semillon marc

Meanwhile the Tempranillo continues to ferment vigorously. We are punching the cap down every four hours during the day. Colour is excellent, a dense purple/red. On the 11th February sugar level was 4.0 deg Baume, so we have just a little way to go until fermentation is complete.  pH is 3.8 but will change ie. increase, as the ferment progresses and after MLF is finished. Our target is 3.6. We will need to do some acid adjustment.
The Cap:  Fully formed; Half punched down; Fully punched down

MLF or malolactic fermentation is the conversion of one of  the natural grape acids, malic acid into the more stable and less harsh lactic acid by lactic acid bacteria. We added a lactic acid culture at the beginning of the fermentation process. MLF is not really fermentation but is called such as carbon dioxide is released during the conversion. Adding the culture early gives it the opportunity to work while the true fermentation is taking place. Waiting until this is over to add the culture (or waiting  for the process to occur naturally) is 'dangerous'  from an oxidation point of view as the lactic acid bacteria are very sensitive to SO2. This could mean no protection for the finished wine for a considerable time.

pH is the measure of acid activity in the wine, not the actual acid content ie.TA or titratable acidity.
We use a simple pen style pH meter. It has an accuracy of 0.05 units and automatic temperature compensation.
pH is important because at the required level (around 3.3 for whites and 3.5 for reds) the wine is protected from microbial spoilage as well as giving many of the chemical additions the best conditions in which to work.
For example, the most active component of SO2 is molecular sulphur. The lower the pH the higher the content of molecular sulphur in the SO2 addition. Therefore this chemical's activity against microbes and oxygen is optimized at the 'right' pH.
Weather forecast for the next 3 days is rain periods. Not drought breaking but 50mm is expected.
I am sure we will be harvesting the Pinot Noir not long after this rain event is over.

Sunday, February 09, 2014

Vintage 2014 Begins

We took the plunge and harvested the Tempranillo on 7th February.
Forecasts were for increasing warm to hot weather over the next week with little likelihood of rain and we had noticed some shrivel (raisining) beginning in bunches on vines growing on the shallower soils.
The co driver is injured so one of her friends, "Annabelle" who has some grape harvesting experience, offered to help.
We wizzed through the rows in a few hours.

Fruit quality was generally excellent despite a little more than expected shrivel. No fungus was apparent.
So the buckets went straight up to the 'winery' where the bunches were crushed and destemmed.
This was followed by the addition of DAP (a fermentation accelerator), a red wine specific yeast and a MLF culture to the 'must' (juice and skins).
Sugar level of the juice was just over 13 deg Baume which is very good. This should produce a wine with an alcohol content of around 13%.
Fermentation began within 12 hours.
This process should take around a week to complete. We will be 'punching the cap' down every 6 hours or so. The cap forms when the carbon dioxide released during fermentation forces the skins into a thick layer on top of the wine. The skins need to be kept in constant contact with the wine to extract as much colour as possible and to prevent any oxidation.
After fermentation is complete the wine will be drained off the skins which are pressed. The pressings with their concentration of tannins and colour are added back into the free run wine. The virtually dry skins (the marc), are then discarded. We return them to the vineyard rows as a source of potassium together with the stalks..
Further processes such as acid adjustment, oak addition and fining / racking will then take place.
Our Vin de Garage Winery

Grape bunches in the crusher / destemmer hopper

Juice and skins (the must) in the fermenter after crushing

Yeast rehydrating before addition to the must

Stalks ejected during the crushing and desteming process.

Friday, February 07, 2014

The Rabbits Are Back!

We haven't seen many rabbits around here for nearly a decade after the calicivirus was released in the area.
But lately we have noticed a few in our front garden and I found the beginnings of a warren in the lower paddock.
Bad news!
Rabbits, an introduced pest, are the scourge of Australian agriculture.

So we have been laying baits around the house and will be gassing the warren.
The bait is oats laced with Pindone which is a anticoagulant.
Warrens are treated by filling up and tamping all the entrance holes except one, then putting a Fumitoxin tablet on a wet piece of paper down the last hole and filling that in. The phosphine gas is formed when the tablet is in contact with moisture. 
Both systems work well despite the fact one has to be very careful handling the Fumitoxin and take special precautions to avoid injury. We have seen positive results from the baiting already with a few carcasses around..

We have heard that the authorities will be re-releasing the calicivirus into our area sometime in February but I think it's better to get on top of things earlier.
And for those who think this is all a bit cruel, read about the damage rabbits do here and be aware that landholders are required by law to control rabbits on their property.
Substantial fines apply for those who don't.
Update: 26/02/14 Calici Virus to be released mid March

Saturday, February 01, 2014

A February 2014 Update

The long spell of warm dry weather continues.
We had a couple of days of sporadic showers which put around 20mm into the ground and was just enough to give the vines a little boost but not enough to cause any berry splitting.
Based on long range weather forecasts, we had instigated a curative spray program rather than a preventative one this season. The latest rain event caused the tell tale signs of downy mildew ie. oil spots, to appear on the surface of some of the untreated leaves.
To combat this as well as any potential powdery mildew, we sprayed with the usual protective copper/sulphur (2g/L each) combination and included a downy curative Agri-fos 600 component (3mL/L).
Within a few days the latter had done its work with small brown spots appearing on the leaves where the downy fungus used to be.

Agri-fos is phosphorous acid and has a systemic action ie. the chemical is absorbed by the leaves and translocated to all parts of the vine through its phloem/xylem system.
And the blue colored residue of the copper spray indicates the good leaf coverage that was achieved with the latest application.
Spraying is a bit of a complicated science involving application rate, droplet size, canopy penetration and coverage (droplets/cm2).
There is some pretty sophisticated machinery around to do the job, not to mention the necessity of knowledgeable spray nozzle selection and sprayer calibration.
Our sprayer is very basic 12V battery powered hand operated model with one adjustable nozzle and we have learnt by experience to apply the most suitable droplet size dependant on the ambient conditions eg.wind speed, at a level of "just before runoff".
Scientific? No, but so far so good.

We have done one full block ripeness (sugar) test on the Semillon. The result was 9.0 deg Baume. This is too low for harvest with our target being 11.5 Be'. So it appears that we need to wait another few weeks.
Tempranillo sugar level as viewed  through a refractometer

A simpler random test of the Tempranillo gave us a result of just under 12.0 Be' (and a pH of 3.5). Our target here is at least 12.5 Be'. So another week or so should do it.
It is a little too early to test the Pinot Noir and way too early to test the Cabernet Sauvignon.
So the Tempranillo result means harvest is just around the corner. The grape variety's name is the diminutive of the Spanish temprano ("early") and is really living up to its name this vintage.
Time to start the preharvest equipment clean up involving tanks, fermenter, crusher/destemmer as well as the collection buckets. I had ordered all the spare parts thought necessary (based on past experience of what can go wrong) late last year so here's hoping all goes without a hitch.
Also interesting is a comparison of the bunch size and berry structure of the three reds.
Pinot Noir


Cabernet Sauvignon

The Pinot Noir is now so compact that any excess rain will cause the vines to absorb a lot of moisture and the potential for the berries to burst. This is an open invitation for the formation of the fungus, botrytis (grey mould), to form. There is really no cure. Botrytis affected grapes generally make poor wine although in some cases, if conditions are right, botrytis can become noble rot producing distinctive tasting and intensely sweet but acid balanced white wines eg. Sauterne.
But we don't need either happening with any of our grapes.
In other news the South Coast Wine Show for 2014 is done and dusted for another year. Entries were down this year but 8 Gold, 10 Silver and 34 Bronze medals were awarded.
More details are available on the show web site.
We have noticed a few rabbits around the place and have begun an eradication program but this will be the subject of another post.
The three new calves are surviving so far.
Other than that we are now enjoying a rather less hectic lifestyle now that the vast number of tourists have left.