New World Winemaker Blog

I remember reading and hearing about the next big thing, ascorbic acid when I was just starting out winemaking. It was going to revolutionize white winemaking and everybody who did not know about it was simply out of the loop. Since then, very little has happened, and the practice is not widely employed. I wonder about things that people propagate as fact, simply why it is not used by everyone, it just seems to be so obvious, you would think. Now the next big thing might be gluthathione (GSH). Yes, did I pronounce that correctly?

When you look at all the chemicals in wine that can act as anti-oxidants, SO₂ is not very high up in the chain, and is much less effective relative to other compounds. The series from “worst” to best would be something like, SO₂, ascorbic acid (Vit C), vitamin E, gluthathione (GSH) and then tannin. In white wine there is not a lot of tannin, so the next best thing would be GSH. Many of the flavourful compounds in wines have thiol groups, and when they oxidise, they lose their flavour. This is where GSH can save some flavour, because the source of its power is its thiol groups, which will take a bullet for the flavour compounds.

GSH gets used by yeast during fermentation, so if you want to add this lovely compound you have to add it after two thirds of the fermentation has been completed, because then the yeast will not assimilate it. GSH can be added in the form of yeast derived products.

Recently someone suggested that the use of ascorbic acid can lower the amount of SO₂ needed, but what would be much truer, is that low oxygen pickup can lower the SO₂ needed, since this is actually what is combated by SO₂. When you are evaluating practices and trying to compare two different wineries, you are dealing with different grapes, lots of different micro components, different bottling practices, never mind different ascorbic acid regimes.

Ascorbic acid started as the thing to do, but practical experiments and lots of anecdotal evidence suggest that it is not as powerful as first suggested. The grapes seem to have a much bigger influence than anything else, and ascorbic is not the silver bullet that it was first touted to be. In a few more years we must look back and see what GSH accomplished.

For  technical article on glutathione click here.

Louis Nel is the owner and winemaker of Louis wines in South Africa.

This is a favourite claim of the so-called “natural” or “non-interventionist” winemaking movement. One of the reasons why they claim it is better to do natural fermentation instead of using commercial yeasts is that commercial yeasts with their “predictable aromatic profiles” can make, say Sauvignon blancs from Europe, taste like New Zealand Sauvignon blancs. Or worse even, it can make Chenin blanc and Ugni blanc taste like Sauvignon blanc. I have personally been in a tasting with a group of oenologists representing most of the wine countries in the world where the Germans presented a Muller-Thurgau. Everyone, including the French (much to their despair) thought it was a Sauvignon blanc. I have also once given a South African Colombard to a group of French winemakers to taste and they also believed it to be a Sauvignon blanc.

So how does this happen and is it “wrong?” The “naturalists” feel it is wrong. Winery sales figures show it is “right.” Consumers like these aromas. Wines around the world can taste similar because we make wine mostly from one specie – Vitis vinifera. Then we also use yeast which originates from mainly one specie – Saccharomyces cerevisiae. Each grape variety is not equipped with a unique set of flavour active compounds. Only the combination is unique. This combination will differ between grape varieties as well as within the same grape variety in different vineyard blocks and vintages. The main aromatic compounds found in grapes are monoterpenes, C13 – norisoprenoid derivatives, pyrazines, thiols and certain amino acids that can be converted to aromatic higher alcohols and esters. The latter two groups are non-aromatic in grapes and converted by the fermenting yeast to a flavour active form. In some cases pyrazines found in Sauvignon blanc are seen as a positive. When present in reds such as Cabernet and Merlot it is seen as a negative.

Thiols smell like guava, passion fruit, grapefruit, black currant and gooseberry. Sauvignon blanc happens to have the highest thiol precursor concentration in the grapes. Wine yeasts convert these precursors to their flavour active forms and differ in their efficacy to do so. Many other white grape varieties contain these thiols but in lower concentrations. So unless you use yeasts that are very good in expressing these aromas and combine it with certain winemaking practices, these aromas will go unnoticed – as they did for many years. However, winemakers around the world are upping their game – competition is tough. They are using modern technologies and as a result they are tapping into these flavour profiles of their grapes that they did not know exist. As a result they can sell their wine in a bottle and not a box. Is this wrong?

Yes yes stone me, I work for a wine ingredients company and I have a commercial interested in winemakers using yeast. However, my clients who’s Chenins, Colombards, Ugni blancs, Muller-Thurgaus and Verdelhos that have “Sauvignon-like” aromas are certainly not complaining about their sales. If you have very good quality grapes then you have many other flavour active compounds that can “sell” your wine for you and you don’t necessarily have to make such an effort to express the thiols. When you have less than top quality grapes, then optimising what you have is a good idea and if that means optimising thiol expression then so be it.

Just for the record – contrary to popular belief I do support natural / un-inoculated fermentations when conditions are right for it. See my earlier blogpost: Natural vs. inoculated fermentations.

In these times we are all becoming more aware of our impact on the environment and the scarcity of natural resources, and going green is the only way to go. Only 20% of the weight of the barrel is used to improve wine quality while the other 80% is used for structural integrity, so maybe it is time for the “plastic” barrel to make a comeback.

Stanley Kubrick’s 1971 movie “A Clockwork Orange”, got its name from the fact that nothing can be as artificial as a clockwork orange, and similarly more than ten years ago there was a very eco friendly barrel on the market, that I called the plastic barrel. At the time there was nothing I could consider more artificial.

Only the inside of the staves were made from oak, while the outer part was made from cheap wood, and the barrel was covered in oak veneer. The barrel was toasted with infra red light and every second stave had a heating element, so that the barrel could be heated to speed up aging, or to stimulate malolactic fermentation. The barrel could be hooked up to the transformer that supplied the electricity to the elements, and a thermometer would be fitted through the bung to monitor and regulate the temperature inside of the barrel.

Wine only enters the first 5mm or so of a barrel and the rest of the oak is wasted, so conserving this natural resource could be highly beneficial. Besides that only 4% of the wood of an oak tree is good enough to be used for making barrels, so you will be saving a lot of trees, while wood that is more plentiful can be used for the structural integrity of the barrel.

At the time I was part of a huge contingent that thought such a barrel is the biggest load of fakery around, but if it lived on we could have had a lot more manufacturers, who could have improved on the concept.

When using staves, a much larger percentage of the oak tree can be used for making staves and the staves have a smaller carbon footprint when transported, because you are not transporting so much French or American air. All the oak is used and none is wasted to keep a barrel from collapsing.

Maybe it is time to revisit the plastic barrel, and look at ways where this “artificial” product can, like screwcaps, low carbon footprint plastic bottles, and staves be used to protect natural resources and hopefully save the planet.

Winemakers love to gripe that Pinot Noir is the hardest wine to make. I disagree. It is not that it is difficult to make; Pinot Noir is difficult to get right. First, if you are not starting with good grapes you might as well pack it in. Americans don’t like to be told this, but all vineyards are NOT created equal. And great Pinot vineyards are scarce on the ground, at least as much so in America as in Burgundy (where less than 10% of the Pinot Noir acreage is designated grand cru). Second, not all winemakers are temperamentally suited to make Pinot. During the winemaking process, Pinot Noir punishes ego. Winemakers who must put their personal stamp on every wine they make invariably make bad Pinot, because tinkering with the process or “fixing” what appear to some winemakers as “problems” just does not work with this grape.

I’m not saying that I’m some sort of Pinot genius — far from it. In fact I believe there can be no such thing — the best Pinot winemaker I can hope to be is some sort of zen-state idiot savant. By practicing this approach to making Pinot for the last decade-plus, I have come up with a few do’s and don’ts. Do start with a good vineyard. Don’t pick the grapes overripe. Do pick when the seeds are ripe. Do treat the fruit gently. Don’t do the whole berry/carbonic maceration thing (in my view, a method that makes Beaujolais, not Pinot). Do make any additions the fruit needs at the crusher. Do wait for the cap to rise on its own (some winemakers call this a “cold soak”). Don’t ferment uninoculated – there is nothing more certain to destroy Pinot than having to “fix” a stuck fermentation. Don’t pump the wine over the cap. Do punch down. Don’t punch down too much. Do let the wine “rest” for a while after fermentation before pressing. Don’t do extended maceration.

It is this last point that had me in a state of cognitive dissonance during the 2005 harvest. The protocol I have developed over the years is to maintain the wine in fermenter for a total of 14 days of cuvaison. For reasons related to the timing demands of the 2005 harvest, the move to the new winery, and delays in receiving new equipment, all my ’05 Pinot Noir lots spent substantially longer than 14 days in fermenter: 19, 22, 27, 28 and 29 days to be precise. And I was sorely afraid.

BUT – so far this has not proven to be a disaster. The ’05 wines in fact are marvelous. Whether they are marvelous because of — or in spite of — the long maceration times will never be known. I have no plans to deliberately incorporate long maceration into my Pinot protocols. Perhaps some day in the future I will have the resources to do an experiment on the effects of long maceration on Pinot. Until then I plan to do my best to keep maceration times near two weeks. But at least I have learned that I don’t have to stress out over not getting the Pinot pressed off at exactly fourteen days. That, at least, is a bit of a relief.

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.