Archive for the 'Enology Practices' Category

Enology: 2005 Yummy adolescence

Monday, December 12th, 2005

In a word, junior high is best summarized as awkward. Even the hot, developmentally advanced popular girl and the big dude that can grow a beard by the end of the day seem out of place amongst sheepish youngsters who always look ashamed as if each momrning they wake up with mixed feelings about last night’s erotic dream. The is a wonderful analogy of where the wines are currently. The great thing is that perhaps much like great parents might indicate the future quality of the awkward youngster, wonderful fruit and a superb vintage is giving us confidence in the outcome of our adolescent wines.

Most of our blocks have now been sulfured, and are improving by the week. Others, still in malolactic, are trying to hide their beauty between buttery lactic flavors and reduction. Nevertheless, we are confident in the wines this year. The Chardonnay is uber concentrated, silky, and the increase in new oak this vintage is integrating seamelessly. The reds are equally dense, with a bit more structure this year, slightly greater acidity and less alcohol. My kind of wine. Reserve some space in your cellar for ‘05, it is going to be a winner as long as we don’t screw it up!

Acetaldehyde production.

Tuesday, November 8th, 2005

Its true, we have a little acetaldehyde in one of our Merlots. Interestingly, in a search through my textbooks and the web, I found a brillant summary on acetaldehyde written by…me! I completely forgot that Dr. Waterhouse would be publishing a portion of our reports on the web. So much for my retention. Does anyone know if its true that just Acetic Acid bacteria and yeasts are the main producers? We are not prepared to sulfur yet because ML is not complete. Just trying to figure out what the spoilage might be, if any (the wine was not exposed to excess amounts of O2, though perhaps the headspace left after barreling down was large enough, for long enough, to introduce a little O2).

Malolacitc Time

Friday, November 4th, 2005

Its malo time for most of us, and don’t forget to consider your diacetyl? How do you like your butter? I never miss it when its not there, and often critcize when it is, so I like anaerobic conditions which reduce its prodcution all together. If some air is getting into the wine via racking, loose bungs, whatever; then don’t forget to wait a week to sulfur, ortherwise you may want popcorn with your Chardonnay. Here’s a good paper.

Enology: wood oxygenation.

Monday, June 27th, 2005

While continuing my investigation into current reports regarding oak and wine I was sidetracked by oxygen diffusion through barrels and microoxygenation. It is difficult to read something about oak in winemaking that does not say that one of principal benefits of oak is slow oxygen diffusion through the staves. I recall some objection to this from Boulton, and vaguely remember reading in the Ven126 reader evidence that suggest diffusion is limited if not nonexistent. If diffusion occurs, why does a vacuum form during expansion and contraction of the wine?

Here is an article from The Australian & New Zealand Grapegrower & Winemaker that is one of the best summaries I have been able to find relating to this issue. Although their citations are limited, they suggest that at most 2.5 ml/litre/month are diffused through the barrel and that this will significantly decline as the barrel becomes ‘winelogged.’ Significant decline? Does that mean after a few months the main oxygen input is from topping? How many times are people racking (I know this depends on the variety)? If diffusion significantly declines, it may become negligible in comparison to the 4ml/litre/racking. Frankly, I don’t really care if oxygen is or is not moving through the staves, as somewhat of a literalist though, I just don’t want to contniue to perpetuate a myth if that’s what it is. I hate saying something because that’s what everybody says, I want to know.

Here is an additional article on micro-oxygenation. Notice the differences (or should I say similarities)between micro-ox and barrel. I don’t have any personal experience with this, does anybody else? If the numbers are true, it is an effective way to improve wine at a lower price point, no? Lastly, the author takes for granted condensation reactions facilitated by acetaldehyde. Did not Boulton’s also reject this hypothesis?

Enology Practice: More methoxy

Friday, June 24th, 2005

Ahhh, that beloved methoxy pyrazine. I have been interested in finding studies that follow its changes and responses to winemaking conditions/practices. Thus far success has eluded me as I have been limited to pdfs downlaodable from the web. This article pertains more to the impact of trellis system and sunlight exposure, but they did make small replicate batches of wine while monitoring 3 different methoxy pyrazines. Besides, the viticulture aspect of this report is suspect and the influence of sun on methoxy levels are well documented. The most interesting observation is that IBMP (isobutyl form) levels increase above that measured in the berry within a day or two of being crushed. I have observed increases in bell pepper aromas with Cab. and Merlot after a day or two in tank as well. Two studies were cited in corrboration that I am trying to obtain. The authors hypothesize that as skins and perhaps stems are crushed, levels will increase. Apparently IBMP from seeds, skins, and stems have been shown to pass into the juice. This is not a new idea but hitherto had only been heresay. Perhaps this is additional rationale for good fruit sorting to remove leaves, stems, and ‘jacks’ from your ferment. Anybody heard any ideas for volatilizing off pyrazines to reduce their level in wines?

Tight Grain Oak

Thursday, June 23rd, 2005

I have recenlty been reading current literature on oak in winemaking. From a number of studies, it seems clear to me that there is no correlation between the ‘tightness’ of the grain and any chemicals derived from the oak and imparted to wine. If anything, species seems to be the most imporant factor (if seasoning and toasting is the same). The American Journal of Enology and Viticulture 50(4) 1999 presents several articles from an international symposium on oak in winemaking. Even if there is no correlation between grain and flavor compounds, some may argue that there is a yet uncharacterised benefit to having smaller grain. However a study in this issue of AJEV compared wines aged in oak made from single trees (i.e. different grain size) and found no correlation. Most variation in wine descriptors was attributed to the cis oak lactone. But if we can’t use grain size, how do we know what is the best barrel for our wines. I think more must be done to establish how differences in oak derived compounds impact wine sensoy description, until then I think it must be obtained by trial and error, i.e. experience, no?