An Australian harvest diary
Langhorne Creek - Week Twelve
Head southeast from the Adelaide Hills and the land flattens out into a wide open plain before reaching Lake Alexandrina and the sea at Encounter Bay.
Situated in the rain shadow of the Mount Lofty ranges, the Langhorne Creek region receives less than 390mm rainfall a year, but viticulture is made possible by the annual flooding of the Bremer River, which only runs in winter.
Planting vineyards on a flood plain may sound peculiar, but on the driest continent on earth it creates a unique growing region. Controlled by sluice gates built into the river bank, vineyards that are flooded for around 24 hours at the end of August each year will then not need watering for the rest of the growing season.
The Langhorne Creek region was originally limited to a fairly compact 400ha (hectares) where this flooding occurs, however since irrigation lines were established in the early 1990s the area planted has expanded more than 15-fold to over 6000ha.
Vigorous soils require the use of specialised vine training techniques – this is not a region for bush vines and even VSP is fairly uncommon on the flood plain. Divided canopy pruning methods such as Scott Henry and Smart Dyson, as well as other two-tier systems that increase the growing area on the trellis, are commonplace. Vines grow quickly in this environment and have cordons reaching up to 20 feet long.
Langhorne Creek was established as a wine region in the 1880s by Frank Potts, and his Bleasdale winery is still one of the largest in the district today. The National Trust listed winery is home to an ancient red gum lever press (pictured, right), which the winery still uses most years for special parcels of fruit.
This is a region of red wines. Cabernet Sauvignon and Shiraz are unsurprisingly the dominant varieties, but there are also some more unusual grapes making a name for themselves here including the Italian Nebbiolo, Sangiovese, Barbera and Dolcetto.
As vintage draws to a close, winemakers in Langhorne Creek are very happy with the quality of the fruit that has been produced. As with the rest of South Australia, the later part of the season was subject to some rainfall but most growers found that harvest began around 2 weeks early – with one winemaker reporting picking Shiraz in February, and another crushing his last fruit on the 20 March.
The 2006 harvest in Australia was characterised by a cool start to the growing season, followed by some very hot spells in January contributing to an early harvest in most regions, and rains arriving in April. A total volume of around 1.9m tonnes is expected, with quality judged as ‘good to excellent’ overall.
Nepenthe - Week Eleven
Hidden deeper in the Adelaide Hills, Nepenthe Wines are also drawing their vintage to a close.
The final batch of fruit, some Cabernet Sauvignon, was crushed on Wednesday evening and now the attention turns to putting the newly made red wines, which have spent time macerating on skins until the desired tannin balance has been acquired, to barrel. In a small winery such as this, individual parcels of fruit of just one or two tonnes are fermented separately in small open tubs, which require manual digging out when fermentation has finished.
The vintage all over South Australia has finished a little sooner than normal and there is a feeling that the 2006 harvest has been somewhat compressed when compared to previous years.
‘The kick off wasn’t that early, but half-time certainly came earlier than usual!’ says winemaker Peter Leske. ‘Overall in the Hills quality looks to be roughly equal to last year, which has pleased a lot of people because 05 was generally considered to be a very good year. I’m particularly happy with the way the Zinfandel’s looking this year.’
You may not have tried many other Australian Zinfandels, but Leske believes that the variety’s mulberry and spice flavours are particularly well expressed in the Adelaide Hills.
However Nepenthe is probably best known for their Sauvignon Blanc, and they are now launching a new range of wines specifically designed for bars and restaurants. The Quest range will initially include a Sauvignon Blanc and a Pinot Noir.
‘We think our Sauvignon Blanc is already food friendly, but the Quest Sauvignon Blanc is slightly lower in alcohol and in a more European style with less tropical fruit,’ says Leske.
Nepenthe are also conducting some yeast trials with new strains of yeast from South Africa that have the ability to cleave and release flavour precursors in the fermenting must to intensify the aromatic profile of the finished wine. Between these trials and the different vineyards and parcels of fruit, in total there will be 37 tanks of Sauvignon Blanc to be graded for blending – so even though the harvest may be over, work in the winery is far from finished.
Petaluma - Week Ten
As the leaves turn from green to gold, the vines are signalling that autumn has arrived.
Recent rains have led to humid conditions and some beneficial botrytis has found its way into a block of Adelaide Hills Semillon that had been left hanging out in the vineyard with just this in mind. As unattractive as it looks, the botrytis concentrates the sugars and acids in the berries, and imparts some unique flavours of its own, to produce intensely sweet and complex dessert wines.
Meanwhile in the winery the clear, settled Pinot Noir juice for the Croser sparkling wine is being prepared for barrel fermentation. Once inoculated with specially prepared yeast, the juice – which was pressed from whole bunch fruit – will ferment in old French oak barriques for between 10 days and two weeks. Six to eight year-old barrels are used so as not to impart any flavour to the new wine.
‘We don’t want to see any oak in the wine,’ says general manager Andrew Hardy. ‘It’s just for the extra oxidation during the ferment.’
Barrels may usually form part of the finishing process of the wine, but fermenting in oak has advantages of its own. The rough surfaces of the casks trap tiny bubbles of oxygen which the yeast feed on, encouraging a rapid onset and even pace of fermentation.
‘It really adds texture and complexity to the finished wine, so it’s definitely worth the hassle,’ confirms Hardy.
The barrels are not completely filled to allow for the expansion of the fermenting wine, and special bungs are used fitted with breather tubes to allow the carbon dioxide produced to escape. Post-fermentation the wine will be racked to tank and settled before blending into the final wine and bottling to undergo the second fermentation.
Next week: Nepenthe wines, another view from the Adelaide Hills
Petaluma - Week Nine
Picking and crushing the grapes may sound like hard labour, but the real work is only just beginning.
Red fermentation requires constant attention if quality is to be maintained. Processing red fermentations is all about extraction of colour, flavour and tannin from the skins of the grapes. Most of the red grapes - cabernet sauvignon, merlot, some shiraz and a little malbec - have finally come in from the Mount Barker area of the Adelaide Hills and the Coonawarra region in the Limestone Coast.
Petaluma use small fermenters for the majority of their best red fruit, which then becomes the Coonawarra label. These vertical tanks are fitted with ‘header boards’ around two thirds of the way up which form a barrier for the rising cap of skins and keep them submerged in the fermenting juice.
'It just gives a really gentle maceration because the skins are held down beneath the juice,' says winemaker Andy Petrie. 'Other wineries might pump over 3 times a day, but we just need to rack and return once and that’s it. Also all the seeds fall down into the cone [at the bottom of the tank] which is below the racking valve so we’re not cycling them over, which is good.'
Seeds contain hash, astringent phenolics, which the winemakers would obviously prefer were not transferred to the wine.
Red musts are inoculated with the specially prepared yeast culture as they are crushed and a ferment will usually last 1-2 weeks. Occasionally the new wine will be left in the fermenter for a week or so after the ferment is dry for an extra period of
Another, more traditional, method of managing a red wine fermentation is ‘punching down’. This manual plunging of the fermentation breaks up and re-submerges the cap. This time consuming and physically demanding procedure must be carried at least twice a day and is only logistically sensible for smaller volumes of wine, and so is reserved for the best fruit, or parcels of fruit that are too small for the other fermenters.
Next week: white fermentation
Petaluma - Week Eight
Petaluma’s wines are well-known, but some of its unique production methods are probably less so.
The wines are crafted in the kind of labour-intensive way that most bigger wineries have left far behind.
‘We use whole bunch pressing for quality reasons,’ explains winemaker Mike Mudge. ‘It minimises maceration of the fruit and gives the best air flow around the bunches, which allows us to get the temperature down very efficiently.’
The fruit is chilled to 2-3 degrees for a couple of days before pressing. ‘Pressing whole bunches is better from a quality perspective a) because it minimises oxidation and b) because it’s gentler, so you’re not crushing seeds and stalks and picking up phenolics.
Also, we don’t add sulphur dioxide so the secondary fermentation in bottle for the Croser [sparkling wine] isn’t inhibited.
Loading each press with small baskets of whole bunch fruit takes five people about an hour, often beginning in the cool of the morning before the sun is up.
After pressing, the juices are held chilled at around 4 degrees until all the fruit has arrived, then each tank is inoculated at the same time with a specially isolated natural yeast culture.
These days it is fairly unusual for a winery to propagate its own yeast, but this is something else Petaluma take pride in every year. ‘With dried yeast you’re not guaranteed an absolutely pure strain,’ Mudge says.
‘We use strains that have been isolated by Brian (Croser) over the years and they give us characters we like in our wines. They’re also better at fermenting at cool temperatures, which is important.’ Petaluma propagates 10-15 different types of yeast using aseptic techniques, gradually growing each culture until they have a large enough volume of living yeast cells to inoculate all their juices.
Meanwhile most mornings the vineyards are shrouded in mist. The cool, damp weather with patchy sunshine continues in the Adelaide Hills. The early rains have taken some winemakers by surprise - this region would not usually expect to see wet weather until after Easter or even the end of April. However almost all the white grapes are now safely in the winery and the red grapes can stand this late-season drink as flavours mature and sugar levels are kept in check by the lower temperatures, so the waiting game continues.
Next week: Red fermentations
Petaluma - Week Seven
24 - 31 March
There could be no greater contrast. Just an hour and a half to the southeast, the dry open valley of the Barossa is replaced by the rolling green landscape of the Piccadilly Valley in the Adelaide Hills. This region is home to a number of small, premium quality wineries, including Petaluma.
Leaving the scorching 34 degree heat of the Barossa, and arriving in the Hills to a day of rain and 17 degrees made the contrast all the more surprising. This more temperate climate sees a fair share of the damper weather – an average of 1200mm a year.
Petaluma crushes around 2000 tonnes, and although this is only half the production volume of St Hallett (itself only a medium-sized winery by Barossa proportions) this makes it one of the larger producers in the Adelaide Hills.
As well as its award-winning still wines, Petaluma is famous for its sparkling wine, Croser, which is a traditional method blend of Pinot Noir and Chardonnay.
Brian Croser (Decanter's Man of the Year in 2004) founded Petaluma in the 1970s, and the winery will be celebrating its 30th anniversary later this year.
All of Petaluma’s fruit is hand-picked and arrives at the winery intact in small bins. These bins are then manually loaded into the press and the juice is gently extracted and chilled while settling. Petaluma source some varieties from as far afield as the Clare Valley and Coonawarra, but the fruit for the Croser arrive from local Piccadilly Valley vineyards.
Along with most other Adelaide Hills growers, Petaluma are in fact expecting a greatly reduced crop in 2006 due to severe spring frosts back in October.
‘There’s one Sauvignon Blanc vineyard where we only got 17 tonnes and we’d usually expect to get 120,’ says general manager Andrew Hardy. ‘Yields are way down this year.’
As if any more proof were needed, Petaluma’s night shift lasted only 10 days this year, when it would usually be necessary to work 24 hour shifts for a whole month.
Next week: Red grapes arrive
St Hallett - Week Six
17 - 24 March
Every vat in the winery is full and grapes are still ripening at a steady rate, so the time has come to transfer some of the completed red ferments to barrel to make space for the arriving fruit. The new red wines are drained from the skins and settled for a short time in tank before being racked off their gross lees into French and American oak barriques and hogsheads, where they will slowly undergo malolactic fermentation.
One lucky cellar hand has the job of digging the remaining skins (which formed the cap during fermentation) out of the fermenting vessel - but the wine pressed from these skins is held separately and considered for blending with the ‘free run’ portion at a later date.
Grenache is one of the last varieties to ripen here, and as ever in the phylloxera-free Barossa Valley there are some very old vines still producing the highest quality fruit. However, even more important than vine age in this case is the clone of Grenache that is planted. Locally the two main clones are known simply as “the pink one” and “the dark one”. While the former has attractive strawberry fruit aromas, as the name suggests the thinner skinned berries produce a lighter coloured wine. The smaller, thicker-skinned berries of the latter clone result in much more intensely coloured and flavoured wines. The best Grenache in the Barossa is grown in the hot sites on the western belt of the valley.
As busy as things are in the winery, there’s still time to be creative and a small parcel of Tempranillo is being treated to some hand-, or rather foot-crafting, with traditional treading of the wild ferment four times a day in an open fermenter.
Next week: The Adelaide Hills
St Hallett - Week Five
10 - 17 March
Ferments, old vines and lizards
Inhale anywhere in the Barossa Valley and you’ll smell a combination of fresh grapes, fermenting must and new wine. And whenever the constant roar of the presses and pumps stops for a moment, listen carefully. You can hear a whisper of ticks and bubblings from the fermenting vessels as the yeasts do their work.
The yeasts’ metabolism of sugars to alcohol happens naturally, but even so they need the occasional helping hand. Pump-overs and drain & return operations remove the fermenting juice from underneath the cap of skins and splash it back over the top, allowing the liquid to drain through and break up the cap.
Both processes aerate the must to provide the yeast cells with the extra oxygen they need to grow. Each operation also provides the function of keeping the cap wet – which is vital for avoiding unwanted volatile acidity.
Old Block ready
The 2006 harvest is moving swiftly and some fruit for St Hallett’s famous Old Block is ready to come in.
Viticulturist Chris Rogers says, ‘You know this Shiraz is ready to come in when the berries just feel slightly soft – we don’t want them to shrivel up like raisins because we want to keep all that freshness.’
All the Old Block fruit is hand-picked, a process which can take several days. Each member of the 15-strong picking party can harvest on average half a tonne of fruit each day. Hand picking is important to preserve the bunches intact and also to protect the valuable old vines, many of which date back to the 1920s and some even further.
There has also been some wildlife in the winery. The vineyard is a natural habitat for more than just the vine, and from time to time some of the other inhabitants find their way into the winery. The Central Bearded Dragon lizard (above) arrived – annoyed but unharmed - in a parcel of Shiraz.
St Hallett - Week Four
6 March - 13 March
After a brief spell of rain the hot sun has returned to the Barossa so fruit is now maturing at a rapid rate, and it’s quite literally all hands to the pumps.
Ferments are now beginning, so once a suitable yeast strain has been selected for each batch, the tank is set to the correct temperature and inoculated. The winemakers at St Hallett are conducting yeast trials with the Australian Wine Research Institute (AWRI) and specially prepared yeast cultures are collected from their laboratory at the University of Adelaide once vintage has begun.
Each ferment must be carefully monitored to make sure the yeast action is progressing and sugar is being converted into alcohol. White ferments are monitored for Baumé (sugar content) and temperature, while red ferments must be monitored regularly for pH, total acidity, Baumé and temperature.
Red ferments are started as soon as the grapes are received and crushed, with the yeast inoculation taking place at the crusher as the berries are transferred directly to the fermenting vessel. Each red ferment can take anything from 6-10 days, and malolactic fermentation takes place once the alcoholic fermentation is complete.
Several different types of fermenting vessel are used for the red wines. The biggest, and most efficient, are the 45-tonne sweeping arm fermenters, which provide an even distribution of skins and have fully automated cooling and pump-over systems. Smaller tanks are used to keep parcels of premium fruit separate, to give the winemakers greater control over the ferments.
However another experiment is taking place this year – red fermentation in barrel. Red fermentations take place before the grapes are pressed, making barrel fermentation a logistically difficult technique. This year though, ten French oak hogsheads have been ordered with doors cut into one end to simplify the process.
‘When you ferment in contact with oak you get greater ellagic tannins,’ explains winemaker Matt Gant. ‘That begins the tannin polymerisation process and gives you greater colour stability. Of course at the same time you’re drawing oak tannins out into the wine so what you end up with is super-concentrated Shiraz.’
St Hallett - Week Three
27 February - 6 March
Unusually, the Barossa Valley has seen some heavy rainfall in the last two days. This is no great problem as long as the sun comes back and allows the grapes to dry and continue ripening – but if the humidity continues, growers will be forced to take action to prevent fungal problems.
St Hallett often harvest some of their best fruit early in the season - in contradiction to the idea that the grapes left to hang are the best.
Their rationale is that if you can manage the water available to the vine and the cropping level well enough to bring on ripe fruit flavours before alcohol levels have soared too high and acid levels dropped too low, then your must will have a naturally better balance.
Hang time? not necessarily the best
‘I call hanging the grapes out for as long as possible “ripening by default,”’ viticulturist Chris Rogers says. ‘Anyone can get high sugar levels and ripe flavours that way. Irrigation walks a fine line: the vines should be struggling, but not stressed.’
St Hallett also uses crop thinning to control the concentration of the grapes. As much as 50% of the vines’ fruit-load can be dropped on the floor if the age of the vines, soil type and weather conditions make it necessary.
Growers – who are paid by the tonne – are not always keen to comply at first, so St Hallett takes the unusual step of leaving a few rows of vines at the original crop level, thinning the rest, and then inviting the grower into the winery to compare the two wines for himself after they are made.
St Hallett sources fruit from all over the valley. Soil, altitude and mesoclimate are important.
‘There’s so much diversity in such a small area. That’s what I love about the Barossa,’ explains Matt Gant. ‘It gives you a huge number of options to choose from when it comes to blending: a full palette of styles.’
Each parcel of fruit is fermented separately, and blending happens only after maturation when the true character of each wine can be seen.
Fermentation of the newly settled white musts is expected to begin next week, and Gant has been trialling a range of yeast cultures for the different qualities they can bring to the wine. The yeast used affects not only the levels of alcohol and glycerol production, but also the aromatic profile of the wine, so using a number of different yeasts brings complexity to the finished blend.
‘Spontaneous fermentation is great, but you’re in the lap of the gods a bit,’ says Gant. ‘Using a range of yeasts gives us components of wild ferment but you’ve got control so you can blend them together. We’re looking to get that complexity’
St Hallett - Week Two
20 - 27 February
There’s a feeling of calm before the storm in the Barossa Valley. The harvest is beginning at a manageable pace, so this is a time of preparation and organisation, which includes creating space for the new wines that will be made over the coming weeks and months.
So some of last year’s wines - which have spent the last 12 months in oak barrels - must now be blended ready for their final rest before bottling.
Meanwhile, just-crushed Sauvignon Blanc fills the air with the aroma of freshly cut grass. The soft grapey flavours only hint at the capsicum and green pea characters in the finished wine, but the characteristically leafy tang of this variety is there in force.
The newly pressed juice is at once sweet, aromatic and mouth-wateringly acidic. Interestingly, the sugar is actually the least relevant to the quality of the wine, acting most importantly as a vehicle for the flavours of the fruit.
Winemakers rate the juice by the intensity of these flavours, which will be transformed into the aroma and flavour of the finished wine.
Temperature is critical in the early stages of winemaking. Once pressed from the skins, the white juice is chilled to 5C and kept to rest and settle for two to three days to allow particles of grape skins and other solid matter to fall to the bottom of the tank. Only when the clear juice is racked off these solids, and warmed to more moderate temperatures, can fermentation begin.
St Hallett - Week One
13 - 17 February
As the ice thaws on the dormant stumps of the vineyards of Europe, vines in Australia are heavy with ripe fruit, and the harvest is just beginning. Grape picking begins in the warmest parts of Australia’s inland regions at the end of January and continues through the colder regions and later ripening varieties until the end of April.
Our tour begins at St Hallett in the heart of South Australian winemaking, the Barossa Valley, before we move South to the contrastingly cooler Adelaide Hills and then cross over the State line to premium Victorian wine region, the Yarra Valley.
The Barossa Valley is of course best known for Shiraz, and this phylloxera-free region is still home to some of the oldest vines in the world, but Grenache and Cabernet Sauvignon also have important roles to play. Semillon is the star white, with Sauvignon Blanc and Chardonnay, and the neighbouring Eden Valley is famous for show-stopping Rieslings.
Barossa-based St Hallett has a relatively small area of estate vineyard, giving them the freedom to source fruit from a number of growers throughout the Barossa and Eden Valleys, giving the what graduate winemaker Jeremy Ottawa describes as 'a full cuddle of what the region has to offer'.
The harvest begins
The aromatic white Sauvignon Blanc is the first variety to come in. Grapes are picked before dawn in the cool of the early morning.
As unromantic as it sounds, machine harvesting is the most quality-conscious option because all the grapes can be brought in within hours of the winemaker deciding it’s time to pick. Waiting for a team of pickers to harvest a several acres of vines in the heat of the February sun could swiftly lead to oxidised, overheated fruit, and loss of fresh flavours.
If you need further convincing, just look at the figures: a crew of pickers might bring in 5 tonnes of grapes in a day, but the machine harvest 3.5 tonnes of fruit an hour. It straddles the vine row, shaking each vine so that the berries fall off onto a conveyer belt running below.
Deciding when to pick is down to science and taste. 'We sample weekly for a month leading up to harvest and then at least twice weekly when they’re nearly ready to pick. We follow Baumés and malic and tartaric acids pretty closely, but flavour is the deciding factor,' says St Hallett winemaker Matt Gant. 'It’s not really that technical, we just pick them when they taste good.'
He's pleased with the way the harvest is going. 'It’s going to be a cracker. It’s all significantly early, and the flavours are all coming on early, which is great. Our main mission is to pull the alcohol levels back on the reds, and there’s an excellent chance of that happening. I’m really most excited about the Shiraz this year. The yield is down slightly and those flavours are really there already.'
South Australia has been victim to some particularly hot, dry weather recently and there has been concern in some quarters over vines suffering heat stress and fruit raisining on the vine. 'It’s been warm, that’s for sure,' Gant says. 'But there were some good winter rains throughout last year and the vines have all got good canopies on them so the fruit has been well protected from the sun.'