Whenever you buy Venetian glass, it does not matter whether it is a small glass object, like beads, vases or bigger items such as sculptures, chandeliers, be aware that you might find air bubbles here and there.
Even when you receive your set of 6 Murano glass flutes or wine glasses it could be that some of them include bigger or smaller air bubbles and even more than one. But why is that if you can get perfect crystal wine glasses, that are produced in Austria or some other country and these never have any air bubbles?
Many people do not realize, that the entire process in the Venetian glass furnaces is really totally handmade from the mixture of the silica blend until the packing. The ovens are like the ones used centuries ago, the only difference is in the fuel, but that does not change the working process. Fire is always fire and the melting pots are also always the same.
There are no controls made by machines or robots, like in the semi-handmade Austrian crystal production premises. The pressure of the ovens there are controlled with an automatic device. At the same time when the glass is picked out of the oven to go on with the blowing procedure it is always picked out from the bottom.
While in Venice it should be known that when the silica blend melts in the ovens and is constantly stirred overnight, the air bubbles, a normal phenomenon during the melting process, tend to go towards the top. The Murano glass masters start any work by dipping their blowpipe into the melted silica and while pulling out the glass mass they also pick up some of the air bubbles which are on the surface.
Some of them are eliminated while working by using the tweezers or scissors, but it is impossible to get totally rid of them. This is the reason why you might get your beautiful Venetian wine glasses including some air bubbles.
In 1928 Napoleone Martinuzzi introduced a technique in Murano called “pulegoso” where chemical agents produce a reaction during the melting process, thus including such a big amount of small air bubbles that the glass itself is rendered mat. He produced a green amphora with this technique, which was shown at the Biennale that year.
Because of its success, this technique was used over and over again especially for cactus, flowers and trees with flowers, mainly by Martinuzzi himself, but later also by other artists and glass blowers.
The name “pulegoso” comes from the Venetian word for small air bubbles “puleghe”. Some designers have experimented with this technique, among which also Toni Zuccheri who introduced an evolution of it in 2007 by using metal straw instead of chemical agents thus obtaining big bubbles and almost craters in the glass mass.
It is up to every single to decide whether to accept air bubble inclusions in Venetian glass or if to consider them a defect. The people in Murano once again would not even raise the issue as it is considered normal.