Correcting a nose of acetone

Acetobacter

Translations for „Acetobacter“

Name (lat. acetum = vinegar; bacterium = rods) for a genus of acetic acid bacteria with several species. Acetobacter can oxidise alcohol (ethanol) to acetic acid under the influence of oxygen. They are viable even at high acidity levels in wine. As they can only exist in the presence of oxygen - i.e. not in an anaerobic environment (without oxygen) - they are considered to be obligate aerobes. Ideal conditions for their proliferation are warm temperatures between 30 and 40 °Celsius, high pH values (low acidity) and an aerobic environment. Acetobacter are used industrially for the production of acetic acid and vinegar.

https://www.sciencedirect.com/science/article/abs/pii/S016816050700685X 

 

AI Overview

Correcting high levels of ethyl acetate (which smells like nail polish remover, glue, or varnish) in wine is difficult, as it is an ester formed from acetic acid (vinegar) and ethanol. Once this fault is present, the options for remediation are limited and mostly focus on blending or advanced filtration

. 

Here are the methods to treat and manage ethyl acetate in wine, ordered by effectiveness:

1. Curative Treatments (Post-Fermentation)

• Reverse Osmosis (RO) / Nanofiltration: This is the most effective commercial method to remove high volatile acidity (VA) and associated ethyl acetate. The wine is passed through a filter that separates the wine into water/ethanol and components like ethyl acetate, which are then treated or removed.
• Blending: If the ethyl acetate is just above the sensory threshold, blending the affected wine with a clean, low-VA wine can dilute it to acceptable levels.
  • Warning: Before blending, it is highly recommended to sterile filter the contaminated wine (using 0.45-micron filtration) to prevent the bacteria from spreading to the good wine.
• Refermentation (for Low-Level Contamination): A slight, active fermentation can sometimes help mask or reduce small amounts of ethyl acetate. This can be done by blending the affected wine with 5-6% fresh juice/must. 

2. Preventive Treatments (During & After Fermentation)

• Increase SO2 Levels: Adding sulfur dioxide (SO2) immediately, or ensuring it is above 30 mg/L free SO2, inhibits Acetobacter and other spoilage bacteria that produce the acetic acid that later converts to ethyl acetate.
• Strict Oxygen Management: Acetobacter needs oxygen to thrive. Keep tanks and barrels filled to the top (properly topped up) to eliminate headspace where bacteria grow.
• Sanitization: Ensure all winery equipment, particularly barrels that have housed high-VA wines, are heavily cleaned and sanitized, as Acetobacter can live on equipment.
• Cold Stabilization: Keeping the wine cold (around 55°F / 13°C) during aging helps slow down the chemical processes that form esterification. 

Summary of Options

Intensity	Treatment Method
High	Reverse Osmosis (Specialized equipment needed)
Medium	Sterile Filter + Blending with sound wine
Low	Refermentation (5-6% new juice)

Note: In cases of severe contamination, such as a strong, undrinkable nail-polish smell, the wine is likely irreparable and should be discarded to prevent contamination of other barrels. 

Kiwi bud break

 

Kiwileaves are so beautiful, and even more so are the fresh new baby leaves at bud break. Today is a grey cool day, but seeing the new kiwi leaves provided a bright spot. 

Bud break!

 We have bud break. Rondo only. Even the one-year-old plants. Last year, it was 2 April. In 2024, it was 28 March. In 2023, it was 10 April.

The Solaris are still tight, as are the Chardonnay. The Pinot Noir buds are still tiny and not developed.  

Donkeys wormed

 

The donkeys got one of their favourite treats yesterday: jam sandwiches with ivermectin. It was a beautiful day, finally, unlike today which is wet and miserable. Seems everything is a couple of weeks early this year. Just waiting for bud burst. 

Wine aroma and flavour wheels

Wine aroma and flavour wheels can be helpful in identifying the smells and tastes that appear in varios wines for various reasons. Our Rondo from two years ago had the distinct smell of acetone, which stems from bacterial contamination. Our Solaris this past summer produced a wine with depth and complexity that was difficult to pinpoint. In both cases, the wheels may help us describe each vintage to its full advantage. 

I find the UC Davis chart hard to read. 

There are any number of sources of the wheel, each with slightly different descriptions. Of course, it can be a chart and not a wheel. 

I like this one. It's easy to read. 

Vine progress

 

Albarino

The vines in the polytunnel are coming along great. The Albarino vines have leafed, as have the Black Hamburg and Muscat de Hamburg. The Ross House white, potentially Sweetwater, has such intricately cut and delicate baby leaves.

Ross House white, Sweetwater

Black Hamburg

Albarino

Muscat de Hamburg

Outside, both the Rondo and Solaris are approaching bud break. The buds have swollen and are showing signs of rupture but no leaf development yet. No signs of life in the Chardonnay and Pinot Noir yet. 

Rondo

Solaris

Solaris

Solaris

Both Alex and I have been hand-pollinating the apple flowers as there are few insects in the tunnel at the moment. Hopefully, we will get some apples this year. 

Argentines are turning their backs on wine

 

Argentina's wine industry is collapsing. Some 1,100 vineyards have shut down across the country and 3,276 hectares (8,095 acres) of grape production have vanished. People in Argentina are drinking a fraction of what they used to drink, and the young people are not picking up the slack. Moreover, the export market is collapsing as younger people drink much less than people used to. If they do drink wine, they are choosing lighter wines so the old formulations are no longer relevant. 

These trends are going to affect markets beyond Argentina and appelation controllé regions are going to have to make changes in their control of vintages. 

Fine weather

 

We've had a glorious run of good weather for several days and a couple more to come. Yesterday, we had a high of 14C and a low of 5C. Friday was even warmer. Alex took the opportunity to spray the vines with an organic substance recommended by Andrew Watson that protects against mildew. It's called Curenox, and it is applied as a spray diluted to Usage 2.5-3g/L.

Curenox (specifically Curenox 50 WP) is a copper-based, wettable powder fungicide and bactericide used to control diseases like late blight, downy mildew, and leaf spots on vegetables, fruits, and ornamentals. It acts as a preventative by disrupting the enzyme systems of spores, is approved for organic farming, and is applied at 1-2 kg/Ha.

Key Details About Curenox:

• Active Ingredient: Contains 50% metallic copper in the form of copper oxychloride.
• Usage: Effective against early blight, late blight, downy mildew, rust, and bacterial diseases.
• Target Crops: Potatoes, tomatoes, fruit trees (apple, pear, cherry), and ornamental plants.
• Application: Generally applied at a dosage of 1-2 kg/Ha, typically with a 7–10 day spray interval.
• Precaution: It is very toxic to aquatic life and should be handled with care, keeping it away from food and animal feed. 

National Agrochemical Distributors Ltd.

Curenox works as a protective contact fungicide, meaning it should be applied before disease symptoms appear.

Meanwhile, the warm weather has caused tremendous changes in the polytunnel over the weekend. Alex left one door open and it was still very warm inside. All the vines have leafed, and we have an early asparagus crop (4 stalks), lots of broccoli, and the Rockit apple is blooming profusely. I love it. 

Happy St Patrick's Day!

 

Yellow clover (Trifolium dubium) is the shamrock associated with Ireland. Not the four-leafed clover that is associated with luck. The shamrock is a delicate three-leafed plant and said to represent the Holy Trinity, which is why it was associated with St Patrick. He used it to explain how the father, son and holy ghost are all one being. 

We have multiple three-leafed and four-leafed plants growing in Ireland, including Wood sorrel (Oxalis acetosella), white clover (Trifolium repens), and Red Clover (Trifolium pratense). 

Meanwhile, in the polytunnel, everything is coming to life. 

Ross House Buckland Sweetwater

Foxford Muscat de Hamburg

Westport convent Black Hamburg

Rockitt apple blooming