KJ: Someone asked at a tasting recently about the benefits of spontaneous or native yeast fermentation. I said that they create little “flaws” in the wine. They are slower building cultures — not the quick, clean commercial yeasts of the 1970s and 1980s — and they produce more complexities, including higher volatile acidity (acetic acid), which merits our attention.

There are usually multiple indigenous yeasts present that start fermenting and add complexity, and then the strongest yeast cultures finish the wine. One facility we know used to be a sparkling wine cellar, so there is a strong bayanus resident yeast population there.

Such resident populations cause us to be very careful in our cellar practices. For example, we have ozone (O3) machines available for cleaning – ozone is the second most powerful oxidant in nature and is very efficient for sterilization. And we have steamers for barrel cleansing. But we don’t want to get too clean.

Why? Because some of the “terroir” can come from off the wall! In Burgundian cellars, the walls have something spongy like moss growing on them. Talk about biodiversity.

Inoculating wines with a known yeast culture gives you a tool. If I were making a half million cases of a given wine, I’d want everything squeaky clean. For small lot production, more and more winemakers are using native yeasts. You need to know what the native strain or strains are in your cellar and how fast they will go. Slower fermentations allow more things to happen.

Heat is important to get the fermentation going. Cold soaks can develop ethyl acetate, so you have to pay attention to that. Then either fermentation begins or you inoculate with a yeast strain that will start it.

NC: In farming, we have been returning more and more to old practices. We’re more green. We use organic practices although we may not go through the paperwork to be certified organic. Organic is more expensive, but we have a more educated clientele who appreciate that. We’re a long way from the heavier herbicides like Paraquat that used to be applied. And the vines show what they get from the earth.

KJ: In Burgundy, they say their soils are finally back to where they were before World War II.

AMR: There was a Carneros Quality Alliance Pinot Noir study in which a UC Davis researcher looked at the microorganisms in the soil. She checked our 490 block and a parcel next to it that was never planted to grapes, and we were pleased to learn that the bacteria and fungi in the soils were not significantly different.

We cultivated every other row, planted cover crops and used very little fertilizer. That organic material breaking down into humus aerates the soil, makes it friable and improves water penetration. These old practices now have a new household term to describe them – sustainable.

I think the trend to organic and now biodynamic farming is a reaction to heavy science and a shift toward the natural and the spiritual. We collectively discovered that DDT and baby formula weren’t that wonderful after all.

NC: The problem was that we lost our connection with natural science.

AMR: Yes, we could read nature, and then our instincts got out of touch.

NC: We’ve had to re-learn to believe in ourselves and to trust our instincts.

AMR: And that process requires a lot of experience. Our tendency is to apply scientific methods and ignore our gut feelings. But often we don’t know enough variables to solve the equation. The art of wine growing is a combination of informed instinct and science.

Yesterday we looked at block 190 and compared it to block 490. You get a feel for the difference, not a definitive measurement. You have the same soil, same water. So you take in the “vibes” of the vineyard – color, nuance, a leaf that’s a little curled, the condition of a short tip, the underside of another leaf. It’s like meeting a person and forming an opinion on their health – you take in their skin color, posture, energy level, a sparkle in their eyes.

NC: We constantly test ourselves by running different variables through the equation and seeing if it seems right. You ask yourself, “I feel this way. Why?”

AMR: Yes, and you have markers. This didn’t happen. Why not?

NC: Most of the time when I go into the vineyard, I feel good. All is well. But sometimes I sense something is different. For example, you can smell the mealy bug. And you can smell mildew.

AMR: It’s a moldy smell.

NC: I know that in block 4-89, there’s more chance for mildew, so I go there and see.

AMR: You know what is normal for that site.

NC: Right, and as we prepare the vines for the next vintage – pruning, maintaining the irrigation and trellising systems, etc. – we also prepare ourselves. What will I do differently based on having been through another harvest?

KC: I subscribe to a form of preparation – it’s called vacation.

AMR: This year is going to be different. Some blocks are through bloom already and some have barely started.

KJ: I’m excited about block 190. You guys made a real difference there. Good stuff!

AMR: By holding it back. But we have to be careful not to stunt growth by leaving it in full cover for three years and holding back too much. That goes to the issue of spacing between vines.

You configure a vineyard based on your judgment of the potential of the soil – will it be a vigorous site or a more restrictive one? But you also have to consider logistics, like tractors. Initially, vineyard spacing in California was based on the size of tractors manufactured in the Midwest for Midwestern agriculture, for farming wheat and corn. So you have to consider your equipment in order to manage and work the block in a timely manner. If you’re not on time, you negate the effects of the best spacing.

Our 490 West and 490 East blocks are different, with heavier clay soil on 490 W. We may leave that block in full cover crop for a year to slow it down, controlling vigor the way we have in 190, just to see how big the crop is.

KJ: Can we determine the optimum cover there?

AMR: Often cover crops don’t get started very well and there are ox-tongues everywhere. Legumes are good when cultivated. They have big, fibrous stalks that aid the soil structure. If they are aggressive, they really suck up the water and nutrients. Fescues would be nice, but grasses are harder to establish and quite expensive. And you can’t be married to that crop – we are grape growers, not cover crop growers.

KJ: It would be good if you didn’t cultivate at all.

AMR: Well, block 190 is in its second year of full cover, and look how it has diminished. Full cover is the most devigorating practice. After a couple of years of full cover, we would cultivate every other row. We would neither cultivate the entire block nor leave cover on the whole block.

With grass cover, you do see more vine stress as well as more nematodes and gophers. It’s funny to see some vineyards going a second full circle back into full cultivation.

Anyway, cover crop is a tool we can’t underestimate. We have to anticipate its effects because it’s hard to bring it back if we’re too devigorating. I’m tempted to cultivate every other row in 490 because we have already brought it under control.

NC: Let’s leave it. You can always drip irrigate.

KJ: I’m just happy with the direction the grapes, and wines, from that block are going. It’s powerful.

AMR: We also like irrigation as a tool. Good spacing comes in because there are more growing points. If your spacing is too crowded, you have more fungus and disease and it’s harder to farm. You may get greater competition, but you also get shading and that can make the fruit vegetative.

On the Sonoma Coast, they planted meter by meter, too tight, and now some growers are pulling out every other row.

KJ: For us, 1,200 vines per acre seems a pretty good number.

AMR: That kind of moderate number works on many levels. It’s easier for various pieces of equipment to work, like any tractor with a picking bin. If your planting is denser, you get more tons per acre, but with 2,100 vines as we have in block 4A07, you really increase your labor. Four tons translates as 3-1/2 pounds of fruit per vine, and the cost per vine is too high.

NC: We have to be aware of how many cuts per acre we’ll make in pruning, or how many shoots per acre we have to pull when suckering. One cluster per shoot means 3-1/2 pounds per vine. You can have 17 leaves per cluster and produce four tons per acre. That’s a commercial yield.

AMR: We tried one cluster per shoot, but Phil (Dr. Phil Freese, viticultural consultant) doesn’t like that. He thinks it’s better to take some shoots out to open up the canopy and average 1-1/2 clusters per shoot by alternating, 1, 2, 1, 2.

NC: After we’re finished, most shoots have one cluster.

AMR: And you can also take wings off the clusters to even them out. If we go to one cluster per shoot too early, the berry size will increase too much.

NC: When the wings are behind, we take them out. In block 4A07, there are bigger clusters and bigger berries. That may be the rootstock, and also we need more water. And all the Dijon clones have large berries, but particularly the 667 that we have there.

AMR: Yes, 115 has the smallest berries, 777 in the middle and 667 the largest. At Nugent Vineyards, they are planted on 4450 rootstock, and the 115 has smaller berries, looser clusters and thinner skins than the 667.