[dgt20 (OP)]

What is the chemistry behind still and sparkaling wine making and what kind of testing do winemakers perform on their wines?

[puppypower]

The chemistry is the same. Both ferment sugars with yeast to create alcohol and CO2 gas. The CO2 gas is vented. The difference is sparkling wine does a secondary fermentation, with a small amount of sugar, in sealed containers. This makes slightly more alcohol and more CO2 bubbles. These CO2 bubbles are not allowed to escape, until the consumer opens the bottle.

You can easily turn any still wine into sparkling wine. However, the wine-kno's ; people who are knowledgeable about wine, might get upset.

[evan_au]

You can also turn any sparkling wine into still wine, by removing the cork for a few days.

[Bastronut]

I would like to know that it is. Is it harmful to the body?

[evan_au]

I would like to know that it is. Is it harmful to the body?

A bit of carbon dioxide turning into bubbles on your tongue won't do you any harm.
The sharper taste of the sparkling wine is due to this carbon dioxide dissolving in the mucous membranes of your mouth and nose, turning it very slightly acidic (carbonic acid).
Your body breathes out carbon dioxide all the time, and has a strong, conscious, reaction to avoid excess carbon dioxide. 

Drinking in some dead (or dormant) yeast cells that were involved in the fermentation will not do you any harm. Your body just digests them.

The fermentation will digest almost all the sugar from the grapes, so in that sense it is safer than sugary soft drinks.

Overall, the greatest short-term risk is that if you have too many glasses of wine (still or sparkling), your reaction time could be impaired, and you may be involved in a vehicle accident (as a driver or pedestrian). Look at the alcohol content to estimate the comparative risk.

Longer term health risks of continued excess consumption include liver disease.