Seasonal update

As I'm back in New Zealand and haven't been here since the beginning of the growing season, one of the things I did was catch up on growing degree day (GDD) accumulation for Lincoln, Canterbury.

The concept of heat accumulation (one way of measuring which is GDD) and how plant growth corresponds with it is an important tenet of modelling the phenology, or seasonal development of plants, and in this case, grapevines.

It goes a little something like this:

Plants need heat to grow. At its most basic, this is because the enzymes that do the chemical work in plants can't function when it gets cold (in fact, this is true for animals as well -it's one of the reasons cold blooded animals hibernate in the winter. Warm blooded animals use energy to generate heat, which keeps the enzymes working). So below a certain temperature threshold, plants won't grow. As the temperature rises above that threshold the enzymes work faster and faster, up until the temperature gets so high as to prevent the enzymes from working again (around the mid 30s in celcius).

So measuring the accumulation of heat during the growing season results in a pretty good match of how far along the vines have come, or what stage they have gotten to. One question, though, is what do you set the temperature threshold at?

Based pretty much on enzyme activity in relation to temperature, 10C is the most commonly chosen base temperature (the temperature below which there is no plant-active heat accumulation). However, this may differ for different types of plants, and even for different times of the season (e.g. it seems that for the process of budbreak, a base temperature of 4C is omre appropriate, and for the first leaf appearances, 7C, Moncur et al. 1989).

Setting aside those special circumstances, a pretty straightforward way to quantify heat accumulation is to take the average temperature for a month (which falls within the growing season) and if it is greater than 10C, subtract 10 from it. That result is then multiplied by the number of days in the month, which gives the number of growing degree days for that month:

[ (average temperature for the month-10) * (number of days in the month) ] = GDD

In other words, on average each day was X amount over 10 degrees, and over the whole month, X times the number of days equals the amount of plant-useful heat that was experienced. Note that negative GDDs are not counted (though it's cold, the plants don't regress - they just sit there until it warms up again)

So to put some numbers in there, if the average temperature of November was 12.6C (as it was at Lincoln in 2009), 2.6C times the 30 days in the month equals 77 GDD accumulated.

If this value is calculated for each month of the year, we can follow the heat accumulation in a useful way, especially when comparing one year to another, or comparing on location to another.

In the case of the former, the graph for the 2009-2010 season looks like this, given the data collected up through November:

Growing degree calculations for the 2009-2010 season (up through November, the orange line) and for the long term average (LTA, the blue line), which is the average over the last 40 years.

The Long Term Average (LTA, blue) is the smooth sigmoidal curve, which signifies that heat accumuation is slower (the line is more horizontal) in the spring and autumn, and quicker (an more vertical line) during summer. The number in parentheses is the LTA GDD accumulation for Lincoln - a paltry 924GDD.

You can see that up to this point in the season, the orange line (current season) is below the LTA line, which means that the season has been cooler than average. If you squint just right, you can make out that the last orange dot corresponds to 77GDD, which is what we calculated above. This also means that there was no accumulation of plant-useful heat in October, or earlier in the season (at least, when based on monthly averages - more on that in another post!).

If you want to compare seasons, this way of looking at the data is fine, but if you want to see the differences more clearly, you can plot the current season's GDD relative to the LTA, which looks like this:

Growing degree calculations for the 2009-2010 season (orange) and for the LTA (the blue line, which is the X-axis). This figure is showing the same data as the previous one, but in a slightly different way.

Now it is pretty plain to see that we're veering away from the LTA. If the line is below zero (the LTA blue line), then there has been less heat accumulation than the LTA, and if it's above, there has been more, and it's been a warmer season.

You can also see more clearly what's happening for each month. If the line moves down, then the month has been cooler than LTA; if it slopes up, then it's been warmer. If the line is parallel to the LTA, then the average temperature for the month has been the same as the LTA.

So what we'd like to see is the line above the LTA - sadly, up through most of December, this has not been the case!

China - the sleeping ice wine giant? (part 2)

And now for the continuation - How China has affected world ice wine production...

Ice wine is deliciously sweet, and due to the many things that have to go right for it to be produced (see part 1) and the low juice yield from the grapes, it is very expensive. So it is very sought after in many places, and also a target for counterfeiters. Some Niagara Peninsula producers were shocked to find that "icewine" was being sold under their brand in China.

There is, apparently, a lot of adulterated table wine being sold as icewine in China, which has a negative impact on the reputation of brands making it the right way, and therefore getting the special characteristics of the wine style that are so yummy.

However, that is not to say that all ice wine being made in China is fake! Changyu winery partnered up with a Canadian company some years ago to develop an expansive vineyard specifically for icewine production. Those Vidal vines are now coming into full production - all 5000 mu (about 333 hectares) of them (there is some confusion over the actual area planted. Some web sources say 5000 acres, but two signs I saw at Changyu say they have 5000 mu (1 mu = 0.067 ha)). The plan is to make icewine under similar conditions as required by the Canadian VQA system, and supply a quality product (Changyu Golden Valley Icewine) to the domestic market.

Changyu Golden Valley Icewine bottles on display at the Yantai International Wine Festival. These are the Golden Diamond wines. There are also two higher price point labels, the Blue Diamond and the Black Diamond ones. Prices for 500ml bottles were 228RMB, 418RMB and 838RMB, respectively. This translated into approximately USD33, 60 and 120, resp.

Some information about the icewine vineyard development. Picture taken in the Changyu Wine Museum, in Yantai, Shandong Province.

The location was chosen so that conditions for quality icewine production would be met most every year, and because the scale is so massive, that means a lot of wine can be produced!

A photo of a photo of the vineyard in Huanren - appropriately icy! Picture taken in the Changyu Wine Museum.

Even considering this is all in China, I still wonder about where they will get all the labour to tend the vines and harvest the fruit!

A photo of a photo of a "Hardworking farmers harvesting grapes in coldness." Picture taken in the Changyu Wine Museum.

And since China does things big, just how significant is this planting in Huanren? In 2008, about 6500 tonnes of grapes were registered for icewine production in the Niagara Peninsula. The Changyu development should produce about 1000 tonnes of grapes (significantly more come from vineyards other than theirs). So a significant boost. Even more significant when the latest info says that only 1750 tonnes were registered to be made into icewine for the 2009 vintage, due to a downturn in the icewine market.

While I'm not a huge fan of the wine style (too sweet for me, generally), it certainly has, and deserves, a place in the market, and is also a good reminder of how versatile a product the grape is!

NB, you might be interested in reading this article, which has more detail on the plantings in Huanren...

Happy New Year!

A cop-out post, I know! However, we've been prepping for the big trip back to New Zealand, and enjoying having Christmas with my parents! So until I can get back to writing another entry, all the best for the New Year! I'll be celebrating with some nice local bubbly!

Cheers! :-)

China - the sleeping ice wine giant? (part 1)

Another chapter in the China travels series...

This time, its about something that was developed in Germany, really took off in Canada, and now it looks like China is poised to take over.

Ice wine. The luscious nectar made from frozen grapes, it is highly prized by some, and highly priced by many!!

Why is it so exclusive? To make the real stuff, the grapes need to be naturally frozen, and picked when the temperature is -8C or lower, and will stay that way until all the pressing is finished (these are Canadian rules - some other countries have their own regulations, but the Canadians seem to have the most comprehensive set, designed to ensure the integrity of their icewine (all one word, as opposed to the generic "ice wine" product)). That's pretty cold, and throw in the fact that it could be windy as well, and you're looking at a temperature of -16, easy, with the wind chill!

Wouldn't it be nice to be able to sit in a mechanical harvester and collect all those grapes into a hopper? It would be nice, but you wouldn't get many grapes that way, as by that time of the year, the cluster rachis has gotten brittle, and the berries fall off far too easily! So the grapes must be hand picked! Sometimes in the dark, when it's the coldest and to ensure that the grapes do not get above -8C. Similarly, the grape press is usually brought outside of the winery and the work done out in the cold. To make it even more difficult, extracting the juice from the grapes takes a long time, so the whole process is one big freeze-fest!

And just what is it about this procedure that results in such a luscious wine? It's a concentration effect. Pure water will start to freeze at 0C, so if you have water with something else in it, those other things won't freeze at that temperature.

So if you take a glass of juice (Kool-Aid was one of my favourites!), put it in the freezer and wait for a while - until it's partially frozen and there's quite a bit of ice in it, take it out and pour the remaining liquid into another glass. Now you have one glass that has ice in it, and another with the juice. If you actually do this, you'll note that the ice (if you wash off any remaining juice) is clear - not coloured like the juice. What you have there is pretty much pure water, which has been frozen out of the juice. If you taste the juice in the other glass, you should notice that it's a lot sweeter, and stronger tasting than the original juice - what you have done is concentrated the juice by freezing out some of the water in it.

The making of icewine uses the same principle. As the grapes freeze, ice forms inside the berry, but all the good stuff - the sugar and flavour compounds - are concentrated. So when the grapes are pressed, a concentrated sugary syrup of juice comes out, which can have twice the concentration of the original juice (the colder it is, the more concentrated the juice). This is what helps to make the wine sweet, and also have its intense aroma and flavour.

And this is why the temperature has to be so cold, and has to stay that way. If the grapes warm up, then there is not as much ice in the berries, and the juice won't have the same amount of concentration.

There aren't too many traditional grape growing areas that have sufficiently cold temperatures consistently, enough to make ice wine. As well, the temperatures can't get too cold, or the vines will freeze and die. Vitis vinifera, which is used to make the vast majority of wine in the world, can survive to around -18C if the conditions are right. So there is a relatively small window between cold enough and "*#!#%*! The vines are dead!!"

Germany was probably the first place where ice wine was made, but the conditions for good ice wine production aren't too common. The Niagara Peninsula, between Lakes Erie and Ontario in Canada is an area that seems to get appropriate conditions pretty well every year, even if they may have to wait until February before they arrive!

Those with quick minds would probably like to point out that this is all very inconvenient, so why not pick some grapes, stick them in a freezer, and press them in there - none of this mucking about in the cold, picking grapes, at least! This technique certainly works, but there is something about having those grapes hanging out there for so long before they're picked that helps to make the wine extra-special. The Cool Climate Oenology and Viticulture Institute at Brock University has done quite a bit of research into icewine production, and they are uncovering some of the factors that affect icewine quality - one of which is likely to be "hang-time" and freeze/thaw cycles.

So how does China come into this discussion? China, as I may have mentioned in passing before, is a big place. They have a huge spread of climates within the borders, and areas suitable for ice wine production are among the country's resources.

Book now for part 2 of China - the sleeping ice wine giant...

China and the Wine City -part 2

The second full day we had in Yantai, the Wine City, we were able to visit the International Wine City, Changyu, established in 2002 (so I was told, though another source suggested that it was in September 2008). This is what I described as the Disneyland of Chinese wine, covering 100ha. Uncountable great busloads of tourists (well, Changyu counts them, and told me that 100,000 visit per year, though the other source said it was as many as 1,000,000 in the first four months that it was open!) funnel through the gates to learn about winemaking, see the spectacle of grapevines growing, taste some wine and grapes and if they come at the right time of year, partake of harvest and even a bit of grape stomping! Entry is a nominal 30RMB each (about USD4.40 or NZD6.10), but the City is used as a way to get people interested in wine, and to learn more about how to appreciate it. They employ a (Western) sommelier to help with this by offering programmes on wine appreciation and the like.

The Grape Tasting Corridor in the Wine City. Here, patrons can sample grapes, wine, and nibble on biscuits, sweets and cheese.

On site is a museum, a huge Chateau, vineyards and of course, a sales room!

The Chateau in the Wine City - a massive and impressive building, meant to spar with the best that France has to offer

All very impressive, and yet, incongruous, as this City is situated in an Yantai industrial park near the south shore of Bohai Straight, between Bohai Sea and Korea Bay, where condominiums reach towards the stars...

Picturesque vineyards surrounded by massive condos, construction cranes and industrial offices

As a viticulturist, I was shocked by the virus status of the vines, which made the vineyards look like a patchwork of red and green. It seems that there is little clean material available, and no guidelines are in place to monitor and try to keep it out of the nurseries. In fact, that would do little to help, as most of the vine material being planted is simply collected from existing vines and poked into the soil. As I've noted before, the sandy soils aren't phylloxera-friendly, so own-rooted vines won't be beleaguered by the pest.

However, vine virus status aside, looking at the International Wine City with a marketing and tourism hat on, it was a marvel. There's no doubt that China is taking the whole wine experience to heart!

Cabernet Gernischt

One of the interesting varieties that I saw in China was this little fellow: Cabernet Gernischt. It is widely grown there, so much so, in fact, that "Jiebaina" (a phonetic equivalent to "Cabernet") has becoming a synonym for Cabernet Gernischt and blends of other Cabernets, much to Chang Yu Winery's chagrin, as they have wanted to lay claim to the name (see here for more details).

Do a search on the web and not a lot useful comes up. Wikipedia as a stub, and there are various entries by outfits selling the wine that comes from China, but there is little else available - not even my hardly-ever-fails-me Super Gigantic Y2K Grapevine Glossary, by A.J. Hawkins has an entry for it!!

Most sources agree that the variety was brought to China (ChangYu lays claim to this, in particular) in the late 1800s, and that it no longer appears to be grown in Europe. The authors of the Wikipedia entry claim that it is the same variety as Cabernet franc, but I'm not convinced about this. I tasted it while in China, and think it's sufficiently different, and as well, there is some scientific evidence that Cabernet Gernischt is not the same as Cabernet Sauvignon or Cabernet franc (see the article by Jiang et al., 2007).

I was told that the non-vintage Cabernet Gernischt is ChangYu's top selling red wine, and that they make 20,000 tonnes worth of it every vintage. That's about a sixth of their present production! I can see why - it's a very pleasant wine - not as big as a Cab Sauv, but a nice accompaniment to an every-day meal. Big less dainty than a Cab franc, but with nice fruit, spice and a hint of perfume.

There is also interest in making a lower-alcohol version of the wine, with Qingdao (better known for its beer than its wine!) coming out with a 9% alcohol version (via reverse osmosis).

Is it possible that this long-lost native of Europe could make a foray back into the West? Never say never!!

China and the Wine City -part 1

The traditional heart of China's wine production is Yantai, a coastal city which is in the Shandong Province, southeast of Beijing. My visit to Yantai was sponsored by Chang Yu Winery, who were large sponsors of the Yantai International Wine Festival, of which the third edition was happening during our visit. As usual, everything is larger in China - even the wine bottles!

At the opening of the Wine Festival. The third incarnation was the biggest and splashiest yet!

You thought things were bigger in Texas? Try China on for size!!

The region is very proud of this international-scale event, which was launched with no small amounts of fanfare. It is aimed primarily at the trade, rather than the buying public, but there were lots of representatives of each group there.

Very little expense spared here - dancers, music, confetti

and parachute-filled cannons, smoke and loud bangs!

Of the interesting things that we saw there was a display of some wines from Central Otago, New Zealand, and also that Chang Yu has a Chateau in New Zealand, where they make the ChangYu Kely brand of wines - a Sauvignon blanc and a Merlot. The vineyard is located in the north - Kaitaia, which is northwest one of the areas first planted with vines in New Zealand, way back in the early 1800s. The winery is Kari Kari Estate, who make a range of wines, and feature one Karl Coombes as Assistant Winemaker - he did the Graduate Diploma in Viticulture and Oenology at Lincoln University in 2007! The Merlot was selling for 298RMB and the Savvie for 318RMB (at the exchange rates at the time, that equated to approximately USD44 and USD47, respectively). In New Zealand dollars, we're talking about $61 and $65, resp. per bottle! Not bad for a bottle that would retail for maybe NZD20 for the Savvie and NZD30 for the Merlot!

Bottle and packaging for ChangYu Kely Sauvignon blanc, sister to the Merlot
also sold under the brand in China.

I was pretty chuffed that the largest winery in China thought that it was worthwhile to have New Zealand wine in their portfoilio, which also favours wines from the Old World as well!!