New World Winemaker Blog

We are taught the benefits of protein stabilization of wines, and accept it as fact. We believe because we are told to. Then sometimes along our wine journey, a suspicion creeps in, we have never seen this “haze” formed by protein instability, is this just another Father Christmas story, one that cannot be true? Like any religion, winemaking has stages, and one sometimes does some church hopping to find the right way of doing things.

When I was a young bright-eyed winemaker, straight out of university, I got excited whenever I met a well-known winemaker. They were my rock stars, and I wanted to be one. What makes them so special, what can I learn, what wisdom can I glean from their fertile minds? I would seek the answer, and go to the mountain and climb it, to find my guru.

At this time I met some of the most decadent rock stars, who told me that adding too much bentonite is just plain evil. It is a conspiracy of the bentonite magnates, who have underground meetings and want to sell tons of the stuff to the masses (this bit I just made up). Bentonite just strips wine, and should be used in very conservative amounts. The recipe the gods gave me was, whatever the lab says, add half of it. If the bentonite requirement was 80g/hℓ, add only 40g/hℓ. I came down from the mountain, and applied this wisdom for a very short while, because I finally found the haze that my lecturers taught me about. Luckily it was a very small run, and did not mean the financial ruin of my boss, but from then on I was a much safer winemaker. I was cured from following gurus for a long time.

There are lots of things that we are taught that we just accept as fact. Most of them are too dangerous to try and disprove, so we might never know the truth. At the other end of the spectrum there are people who get away with bad winemaking practices, because they have a cool cellar, have wine that is not prone to pinking, have a naturally low bacteria count in their wines, have naturally low Brett counts and other blessings. The impact of moving to another cellar where things are not the same as at home, can, however, be disillusioning.

Count your blessings, because you do not know, what it is you don’t know.

Cold stabilisation of wine is one of those things that is very difficult to determine. When is a wine stable, and under which circumstances is it stable? The method used to determine the level of cold stabilisation will determine that. At one time the water bath method using electrical conductivity as a measure was popular, but it actually only determined the level of cold stabilisation at 0°C. The minus four degrees centigrade freezer test, determined the level of stability that the wine will have under those circumstances, and not necessarily for a longer time, and at a lower temperature.

With all these philosophical headaches to contend with, the only proper way of stabilisation was to keep the wine cold for a very long time, or to seed it with crystals at a very low temperature. The effect was that the wine was often exposed to oxygen at very low temperatures where it can dissolve very easily, but it would only react at higher temperatures. Apart from these negatives the energy usage, cost, lowered total acidity and loss of carbon dioxide gas was a worry. Often wine had to be sparged with nitrogen inline after stabilisation to push out oxygen, while removing CO2, possibly flavour, and the nitrogen itself dissolving at low temperatures, foaming when the wine is mixed at a higher temperature. The biggest drawback in future will be the energy used during this process. After this long list of negatives, one would think that there would have been alternatives by now. Well there are, sort of.

Being an avant garde winemaker in my youth, I dabbled with mannoproteins even before they hit the shelves. Here was a product that would keep all the valuable attributes of the wine, without any of the negatives of cold stabilisation. The only drawback was that it only worked so-so. The product was too dodgy to use on big Tesco orders, and the amount of comebacks was always just below the threshold for concern, but only just. At bottling time I would often find that the mannoproteins would form a slimy layer on the filter sheets, and sometimes even block a filter. This meant that some of the proteins where being filtered out. I tried to compensate for this by adding the mannoproteins during bulk filtration, thereby filtering and dosing it at the same time, but I never knew whether the difference was just in my head. All said, Australia shunned the product until other countries stopped experimenting with it.

Another alternative for stabilisation is electrodialysis. This procedure involves a membrane that, at room temperature, removes destabilizing ions, potassium, calcium, tartrate salts using quite a low current. The energy usage is very low, but the capital requirement is quite high. Many people are touting this technology as the next big thing, because it does not seem to lower the TA significantly, and also (apparently) seems to improve the sensory aspects of wine.

The latest technology that is making my tail wag is the use of CMC. CMC is carboxymethylcellulose, and it was recently legalised by the OIV. CMC is used in food as a viscosity modifier and emulsion stabilizer. CMC works the same way as mannoproteins inhibiting crystal growth, and is added to wine just before bottling. The only negative aspect of CMC is that it is not a natural product, and if not used, has a relatively short shelf-life. The OIV specified that CMC’s used for winemaking must be of wood origin, so that would help a bit for the conscience.

I hope CMC is what it is cooked up to be, because it could be a wonderful breakthrough.

There is an old story doing the rounds about one of the pioneers of the South African wine industry. The story, that will never be verified, says that the wine that always stood head and shoulders above that of its neighbour’s, was made in the early eighties by picking the grapes extremely ripe and then adding water. The fruit intensity and softness of the wine’s tannins were unknown at the time, and the wine was very popular.

In the USA the humorously named practice of humidification and more officially named, rehydration of grapes is quite legal. The California Wine Institute sought official approval from the authorities for adding enough water, to replace that which was lost from grapes through field dehydration, and it was granted. The exact amount of water that can be added is not stated outright, but it could be very high. Water is also allowed in California to bring the sugar down to a level that will prevent stuck fermentation.

In Australia a maximum legal amount of 70ml of water per liter of wine may be added, but only during the normal course of winemaking, and not necessarily for the dilution of wine or juice. There are rumours that the practice of the addition of water derived from reverse osmosis is also used from time to time, since it is derived from grapes anyway.

All the practices of water addition that I mention here are to improve the wine and not to dilute it. It is there to prevent stuck fermentations and to improve the flavour and tannin structure of the wine while not having ridiculously high sugar levels.

South African law will soon be catching up, and a recent notice from Wine and Spirit Board stated that, “Pending further directions from the administering officer of the Liquor Products Act and the Wine and Spirit Board, water will be able to be added to certified wine for the correction of moisture losses in grapes. We will let you have above-mentioned directions as soon as they become available.”

Are you as tired as I am of all the winging over high-alcohol wines?

Yes some, perhaps many (but not most) wines over — what? — like, 14%-14.5% alcohol by volume? — might strike some tasters as “out of balance.” Certainly any “high alcohol” wine is a risk to drink too much of when one has driven to dinner. But then so are wines with less alcohol, or beers, or cocktails. Yesterday Jon Bonné added to the drone of high-alcohol criticism in his posting to the “Thirst” column at SFGate… with the statement:

The high-alcohol drumbeat isn’t new, but it is prompting more of a backlash. Increasingly, a new guard of winemakers is dismissing old saws about “physiological ripeness.” They’re deliberately, even defiantly, picking grapes with less sugar. Ripeness isn’t California’s challenge anymore; now it’s balance. That means farming smarter. (And not simply removing excess alcohol after the fact.)

I have not met Jon Bonné but I have read him for years — IMHO his writing is often smart and to the point. This bit is not. I’m not sure what “new guard of winemakers” he has been talking to, and I’m not sure what “old saws” he is referring to, but picking grapes solely on the basis of “less sugar” — whether deliberately, defiantly, ignorantly or otherwise — without considering physiological ripeness is definitely not likely to result in a better wine.

I wish (as perhaps does Mr. Bonné) that the definition of “physiological ripeness” for wine grapes was simple and concrete. It is neither. In fact physiological ripeness is an ideal, an unrealizable goal: the perfect overlap of the development of many enologically important components of the grape skin, seeds and pulp. When considering whether an individual grape is “ripe” one could consider the sugars, acids, pH and potassium in the pulp or juice, the anthocyanins and tannins in the skin, the tannins in the seeds, and the aromatic compounds present throughout.

During ripening each of these things is changing with time: some are going up, some are going down, some are going up and then down. “Physiological ripeness” is that moment when all of these things are in “perfect balance” — exactly where they must be to yield a wine of complicated and soul-satisfying deliciousness. Except that it never happens.

In most vineyards, most vintages, some part of the equation peaks too early, or too late. In many California vineyards sugar arrives too early, before the other things that make a perfect wine grape reach their optimal concentrations. It takes some seriously smart farming to make sure this doesn’t happen.

Notice so far I’m still dealing with an idealization — a single wine grape. In the real world each grape on a cluster, each cluster on a vine, each vine in the vineyard is pursuing its own course to “physiological ripeness.” Sure they are all going in the same direction at the same time but like a herd of lemmings running to the sea, some get there before the rest. As a winegrower it is my job to slow that herd up, to bunch them together as much as possible, then snatch them off before most of them have a chance to go over the cliff.

Someday I might write a book on what goes in to assessing grape ripeness and what steps I might take to bunch the crop up. I would include all the other factors that go into the decision of when to pick: things like lignification of the rachis, leaf senescence, disease status, insect pressure, weather forecast, and even the mundane logistical things like the availability of labor, trucking, and tank space. But not tonight.

The bottom line is that no winemaker wakes up one morning during harvest and says “uh, duh-oy — I’m going to pick at lower sugar because high-alcohol wines are really icky.”

If tastemakers want to make high-alcohol wines go away they should stop giving them medals and high point scores. Consumers could make them go away if they would just stop buying them. I’m not holding my breath. In the meantime, bashing “the trend toward ever higher alcohols” will continue to be a reliable trope for trade writers to sell a few more column-inches — and to rile up people like me.

This post originally appeared on John Kelly’s blog: “notes from the winemaker.” John Kelly is the owner and winemaker of Westwood wines, Sonoma, California.