So...The Dooker Shake.
Wine contains acids, in fact it is pretty acidic compared to most foods we consume. Acid is measured in pH, the lower the pH number the higher the acid. Most wine is between 3.3 and 3.7. Most tomatoes are 4.0-4.8, beer 4.0-4.5, lemons are 2.3-2.7, meats are over 6.0, carbs usually over 5.0.
Acid acts as a natural preservative in foods. The more acidic a food (low pH) the harder it is for bacteria, yeast or other organisms to grow. This is the idea of ceviche or squeezing a lemon on raw food. The acid will 'kill' any bad things on the protein.
Below 3.0 pH most of the things that will attack a wine will be killed by the natural acidity, but above 3.0 pH the risk of an infection in the wine increases. At right around 4.0 pH all of the yeasts and bacteria we worry about in winemaking will survive.
So what nature has forgotten we have to stuff with Potassium Metabisulfite, or as we usually call it sulfur. The sulfur will protect the wine from bacteria. 30+ years ago UC Davis developed a sliding scale that winemakers everywhere (except strangely it would seem in Luxembourg) use. The lower the pH the less sulfur you have to add to kill off the bacteria. The higher the pH the more you have to add to get the same effect.
The amounts are small. At 3.4 pH you need about 30 Part Per Million of sulfur (30ppm) at 4.0 pH you need about 80ppm. So in a bottle of wine it's a difference of fractions of a gram. Still the effect on the wine is dramatic. At 30ppm the sulfur is really undetectable. At 80ppm it's very dramatic. You don't smell burnt matches, that's a different sulfite, but what you do get is a sickly sweet, sharp or chalky smell.
There's a whole lot of chemistry here I'm not going to cover, including exactly what the sulfur level is (we measure free sulfur and total sulfur separately for instance) but basically the higher the pH the more sulfur you need and the more the wine is going to smell and taste of sulfur.
Sulfur though is easy to get rid of in a wine. Sulfur bonds with oxygen and the sensory impact dissipates quickly. That's one reason we try to limit oxygen contact inside the winery. We can keep total sulfur down and our additions low buy not introducing oxygen to the wine.
The Mollydooker shake is a way to get around this effect. That wine has a high pH (probably over 4.0) and so has to be bottled with a high sulfur level. To most people that results in an unpleasant wine. Especially when you first open the bottle. The idea of the shake is to introduce oxygen to the wine quickly and lessen the impact of the sulfur through the molecular bonding taking place. A little oxygen and a few shakes and the sulfur drops to a level that is not so offensive.
This is already super long but I wrote a blog about it here if you'd like to read further: