Some remarks on low-intervention winemaking

words

“Low intervention” is not a legally defined term, so unsurprisingly there is no real consensus about how to apply it.  All winemaking is intervention of some sort.  If you do nothing, grapes will ferment and turn into moldy vinegar all on their own.  Wine is a product of intervening in this natural process, and winemaking is the craft that shepherds grapes along microbiological and chemical pathways to points of stability and deliciousness somewhere in between raw fruit and a sour, moldy mess.

My top two (more or less equal) priorities are to make wine that (a) tastes good and (b) expresses the potential of the vineyard in an upfront and approachable way.  I release wines on a pretty quick schedule, with most wines going into bottle after only 6-10 months in the cellar.  At this point, the wines are still very “primary,” in that they largely express youthful fruit characteristics rather than balsamic notes of age or other age-derived complexities.  The processes I use in winemaking aim to maximize the expressiveness and openness of the young wine without lots of distracting flavors derived from underlying microbiology or new barrels.

So it’s fair to say that I want my wine to taste of the grapes more than of the process, but if you push me on this I’m not sure I can say that there is a sharp line between the two.  For me, “low intervention winemaking” is sticking to processes that don’t amplify or introduce non-grape flavors/aromas and don’t suppress grape flavors/aromas. This is generally what I try to do, but as you’ll see below, I am cautious about using this expression to describe any winemaking approach.

the role of sulfur

In any case, one of the great suppressors of grape flavor and aroma is sulfite.  Sulfites do a great job of helping a wine last in the cellar and age gracefully, but in my view, at conventional dose rates in young wines, they substantially mask flavor and aroma.  My winemaking process aims to minimize the role of sulfites.  I try to keep the yeast healthy so that they totally finish the fermentation and leave no sugar behind for other microbes to eat; this suppresses the activity of undesirable microbes even better than high sulfite doses, at least for the kind of early-drinking wines that I make.

The yeast and bacteria that complete the fermentation of the grapes can also have a profound effect on the flavor of a young wine.  As wines age, the specific flavors/aromas of different yeasts tend to converge, but with wine that is made to be consumed young, these yeast derived flavors can sometimes dominate subtler grape flavors and aromas.  I choose to ferment all my wines with a selected, very neutral yeast strain.  This is a strain that ferments well cool, ferments slowly, finishes reliably, and does not contribute much to the aroma/flavor of the wine.  A cool, slow fermentation develops and preserves fresh aromas from the grapes, minimizes the flavors due specifically to the microbiology of fermentation, and minimizes the sulfury, reductive aromas associated with stressed yeast (“reduction” is a wine-makers’ catch-all term for the presence of reduced sulfur compounds, which tend to have strong, often unpleasant aromas).  The particular yeast that I use was isolated from a natural grape fermentation at the Wädenswil research station in Switzerland.  It is a product of industrial microbiology only in that it is propagated in a factory.  It is a natural yeast, not a product of bio-engineering.  Because of the strong impact of yeast on the flavor of young wines, a non-inoculated wine—a wine fermented by the yeast found in the vineyard and winery environment—may have a very strong yeast character to the detriment of its expression of grape characteristics, especially in its youth.  While inoculating the grapes with selected yeast seems at odds with some of the ideals of, e.g., natural wine, in my context it is a decision to prefer and amplify the natural quality of the grapes and the flavors they develop at their specific vineyard sites over the flavor potential of the specifically microbiological environments of the vineyard and winery.  

the winery environment

You might have noticed that I slipped “and winery” into that last sentence.  There is a part of me that sees the yeasts that have collected on the grapes in the vineyard as part of the character of the site that I might want to express in the wine.  But I work in a shared winery space.  Cross-pollenation in this winery context is inevitable; even if all the equipment is meticulously sanitized (and it is—most of winemaking is actually cleaning), the air easily enough transmits yeast cells from one open-topped fermenter to another.  Given the context I work in, the choice isn’t whether or not to inoculate the wine, it is whether to choose the strain that I use or let other winemakers choose the strains.  Faced with that choice, ultimately I prefer the camaraderie and the economic befits of sharing equipment, space, ideas, and labor over the loss of some of the microbiological aspects of terroir.

filtration

Filtration is another intervention (like yeast choice) that has a profound effect on young wine and less of an effect on wine as it ages.  Filtration often makes white and rose wines taste brighter and cleaner up front, and this is often desirable.  But in wines that have substantial tannic structure or depend on tannin for their overall profile (red wines and amber wines, which is all I make), filtration can often diminish quality for several months.  Big, tannic wines usually bounce back well from the rigors of filtration after a few months or a year in bottle, but with my quick release schedule, I try to avoid filtration whenever possible.  Filtration also involves pumping at high pressure and a lot of potential opportunities for oxygen ingress.  Since the main weapon against oxygen is sulfite, I also prefer to avoid filtration (and generally to only minimally move wines during aging) so I can get away with lower sulfite levels.

beyond grapes and low doses of sulfite, what goes into the wine?

Apart from grapes, I also use grape stems, oak, oak tannin, and yeast hulls/cell fractions as part of the winemaking process.  Of these, the stems have the strongest impact on flavor, oak has a noticeable impact, and refined oak tannin and yeast hulls/cell fractions are process aids that have essentially no effect on flavor, but they let me protect the crushed grapes from spoilage before inoculation and then ensure that the yeast finishes fermentation without contributing lots of distracting sulfide and stressed fermentation aromas to the young wine.

stems

When I say I “use stems,” what I really mean is that I don’t remove the stems before fermentation.  My main grape quality control is in the vineyard.  The day before harvest, I meticulously go through my rows and drop fruit that I don’t want in the wine.  During harvest, when possible, I work along side the pick crew to remove leaves and anything undesirable that might make it into the picking bin.  This up-front attention to quality means that I don’t need to sort the fruit at the winery.  I just throw on a pair of sanitized boots and jump on the grapes till the bin starts to get juicy.  The whole clusters mat together so the grapes crack more easily rather than scooting around without cracking.  When fermentation is winding down, and it’s time to press, the stems provide great pathways for escaping juice and improve press yield without requiring super high pressures.  Stems also provide fresh and earthy flavors of their own and enhance citrus pith and herbaceous aromas in the wine.  These are substantial flavor modifications, but in my way of thinking, the stems are just an integral part of the grape cluster, and I make harvest decisions on the basis of both the flavor of the grapes and the flavor of the stems (you can learn a lot about what a stem will contribute by chewing on the cut end; stems don’t need to be brown and woody to contribute positive flavors).

oak

When I say I “use oak,” what I mostly mean is that I use oak barrels to store the wine during the last days of fermentation and through aging.  My barrels are all pretty old, so they don’t contribute much wood/toast flavor, but they always contribute a little bit of character.  Think of the barrel like a tea leaf.  The first time you steep it, a lot of flavor comes out.  If you steep the same leaf again, you get different flavors and generally less flavor.  The third time you get less flavor, and so on, but you can probably brew the same handful of tea leaves fifteen or twenty times before they contribute no flavor whatsoever to the hot water.  Barrels work the same way.  We usually call a barrel “neutral” after it has been used 2-4 times, but that doesn’t mean it contributes no flavor whatsoever, it just doesn’t contribute that dominant and distinctive flavor of newly toasted oak.  Barrels also allow a tiny, metered amount of oxygen into the wine.  This super low dose of oxygen softens the tannin and takes some of the edge off the young wine.  I prefer to use thick-stave barrels when I can to limit the oxygen ingress without cutting it down to zero. I sometimes eye stainless steel drums as an alternative aging vessel, but so far cost and experience has steered me toward oak. There will someday be an amphora in the program, but y’all need to buy a bunch of wine before I can afford that.

In some wines I like to add a small quantity of new oak to the mix.  My lots are so small that the whole lot usually fits into like three barrels.  If I bought in a new barrel to use in a lot that size, the result would be 33% new barrel impact in the final wine, which would be reasonable in a big Bordeaux-style red wine, but far too high given my stylistic goals.  The alternative I use is to toss a couple of staves of toasted barrel wood into a neutral barrel to steep in the wine as it ages.  This lets me add a touch of new wood flavor when it seems to enhance the grape character, but at a restrained impact level of say 5-10% new barrel flavor, rather than having to integrate the full impact of a whole new barrel into a small lot.  I only add oak staves to red wine; there are a handful of grape varieties that just feel a little naked to me with zero new oak character, like Cabernet, Zinfandel, and Merlot.  When I use varieties like that, I will often use a very small quantity of Oregon white oak (Quercus Garryana) to deliver that background note.  To me this feels like it goes against the “minimal intervention” ideal of trying to maximize the expression of variety and place, but in these circumstances it serves the equally important ideal of making the wine as tasty as possible.  Even in these cases though, the grape characteristics are at the fore, and oak is playing a background role.

(The use of toasted oak staves, blocks, chips, and shreds to add oak character is common in the wine industry.  It gets painted pretty uniformity and negatively as a cost-cutting measure that delivers one-dimensional oak flavor, but this critique does not account for the range and quality of oak products available, and does not account for the wasteful absurdity of replacing perfectly sound barrels every couple years with new ones with just because their inner surfaces have lost their toasty flavor.  In my case, because of the scale I work at, I simply can’t achieve anything between zero and far-too-much oak flavor without using these non-barrel oak products.)

modern interventions with historical precedent

I try not to cultivate the impression that I make “natural wine,” at least by any specific definition of that term, but I certainly have a lot of the same ideals as many natural wine producers.  For anyone who expects that my wines are natural wines, the admission that I use refined oak tannin and yeast cell fractions would be understandably disorienting.  I use these additives to shape certain parts of the fermentation process, and I choose them because they have little to no effect on the flavor of the wine.  In both cases, they help prevent undesirable microbiological flavors from dominating the wine, and allow the grape flavors to remain front and center.  They also fit together as part of a strategy for minimizing the use of sulfites, which do have a strong (I think negative) effect on the flavor of wine.

Adding tannin to protect the must before fermentation gets going and adding yeast fractions to help the fermentation finish are modern oenological equivalents of ancient practices: fermenting in freshly scraped oak fermenters and re-pitching the yeast remains from the previous vintage as a way of kick-starting fermentation.

The former practice was common (in one form, at least) in the French winemaking tradition until modern methods of hot water sanitation became common.  A typical protocol in preparing for harvest was to scrape the inside of wooden vats to expose virgin wood and then sometimes splash it with a little Marc (pomace brandy) and set it alight for a moment to sanitize the surface.  Adding a low dose of refined oak tannin at the very beginning of winemaking, before the yeast have started fermentation, has a similar chemical effect on the wine.  In either case, these highly reactive tannins have a minimal flavor impact, but provide anti-oxidant protection and also bind with and inactivate enzymes in the must that diminish color and promote oxidation.  I’ve done this test side by side and found no flavors that I can attribute to the added tannin, though there is a generic “fresh” quality in these wines that might be due to the removal of enzymes responsible for enzymatic browning and oxidation (think of the difference between biting into a perfect apple at lunch vs. an apple that was sliced and packed in Tupperware in the morning; they taste similar, but the cut apple tastes just a little less fresh).  In many situations I believe this is a less impactful and more protective measure than using sulfites at crush at conventional dose rates.

The precedent for adding yeast cell fractions as a nutrient to help ensure complete, clean fermentation is much older.  I’m going out on somewhat of a limb here, but based on textual and archaeological investigation of ancient Mediterranean winemaking, we have every reason to suspect that the lees (the settled solids) from one vintage would be mixed into the juice coming off the press in the subsequent vintage, nominally to kickstart fermentation.  This would have been an important intuitive, but pre-scientific way to carry over the microbes responsible for a good wine into the next vintage.  But after a year in a buried amphora, the vast majority of these cells would have died and started to break down.  The few viable cells that were left would be able to use these byproducts of autolysis (cellular breakdown) to strengthen their own cell walls for repeated budding and division now that they have been reintroduced to a nutrient and sugar rich environment.  Modern yeast hulls and yeast cell fraction products make exactly these same sorts of building blocks available to the yeast and help them maintain healthy cell walls, survive, and reproduce through the rigors of fermentation.  The more I’ve come to understand these products and see them in light of ancient historical practices, the more I have committed to using yeast derived additives as the main (and now usually sole) source of supplemental nutrition for yeast.  In the past I used a small quantity of inorganic nitrogen to supplement low nitrogen grapes.  I’m not going to rule out inorganic nitrogen dogmatically, but my hope is to avoid it in the future; in any case, my addition rates have always been far lower than industry standards and recommendations.  Part of my decision to ferment in a cold cellar is to slow down the rate of fermentation and reduce the stress on the yeast from being in a low nutrient environment.  Some yeast cell fraction products do have a substantial impact on flavor, but I avoid products that make notable and specific flavor contributions.  In the end, a complete fermentation leaves the wine with essentially no food for other microbes to consume, and this helps keep the wine to be microbiologically stable without adding sulfites to suppress spoilage microbes.

One might reasonably wonder why the yeast need nutrition at all beyond what’s in the grapes.  My answer has two parts: (1) Apart from a few selected areas in the region, most Washington and Eastern Oregon grapes have very low nitrogen levels at harvest, and would have trouble sustaining a healthy fermentation without supplementation.  Some of this surely derives from viticultural practices, but the scope of this pattern seems to suggest that environmental or climatic factors are also important.  (2) Also: they don’t need it.  You can make great wines from nutrient starved yeast, but they tend to need a long time in the cellar to work through their stinky, awkward phase.  I want to capture the brightness, freshness, and liveliness of the grapes and make wines for early drinking, and this stylistic goal is not compatible with long cellaring to resolve sulfide and other issues from stressed fermentation.  I use supplemental yeast nutrition because it helps me present the potential of the vineyard in the most direct way I know how.

the craft of winemaking

In the end, these are practices that let me make the wines I want to drink and share.  Other producers have worked tirelessly to find the practices that let them make the wines they want to make, and I wouldn’t suggest that they go down a different path.  Winemaking is a craft.  It isn’t a sacred ritual, but it also isn’t a science.  As with any craft, the craftsperson makes use of tools and techniques, applying them in light of years or decades of experience, but also in light of an aesthetic ideal.  One of the myths of winemaking is that wine is made in the vineyard, i.e., that everything good in a wine comes from the specialness of the place and the care in farming.  As with every good myth, there is something to this.  You can’t make great wine without great grapes.  That’s why every winemaker wants to be as close to the viticultural process as they can be.  But when we repeat this myth without further comment, we propagate the idea that good winemakers just get out of the way and let grapes do their thing.  The truth is that our craft is exactly to get in the way of letting grapes do their own thing.  The cachet of low-intervention winemaking as a concept is alloyed with this myth, and to that extent, it also needs to be explained and articulated if we’re to be open about the craft of winemaking. I might prefer a term like “low impact” winemaking to describe my process, since I want to clear the way for the fruit to express itself, but given the range of stylistic choices that go into selecting the mode of this expression, it is hard to maintain the idea that the grapes have anything to express without relation to an aesthetic ideal imposed by a craftsperson who shepherds the wine from vineyard to bottle. This leads me to describe the wines as “open source” wines. Rather than trying to classify the process I use, I would rather just explain the things I do and why I do them.

Whew. Cheers if you made it to the end of this one!