Background information about the historical glass

The glasses are mouthblown and handmade by Czech craftsmen according to the long established traditions of “forest glass”.The name “forest glass” comes from the glassfactories of the 16th and 17th centuries who were mainly located in the forests of Northern Europe. The wood was used as fuel to heat the ovens where the raw materials were melted. Then the ashes, together of course with the sand, were combined as being the essential ingredients for glass manufacture.The colour green came from the sand of this region which contained traces of iron ore and this, together with the copper oxide added to the ground wood ash, explains the greenish characteristic of many glasses of the period.As wood-fired ovens could only heat to about 800 ºC, very often the raw materials were not entirely liquefied. This made glass blowing even more difficult and explains the irregularities which makes each glass unique.
Glasses over the centuries.

In the 14th century glass tableware mostly consisted of enormous goblets for serving beer.

The entire surface was studded with small glass nodules to ensure greasy hands could get a good grip in a pre-knife and fork era.
Over the following centuries and especially as from the 17th, the glasses became more refined and the handholds more decorative. It was around this time that ‘balloon’ glasses were introduced, with the glass itself smooth and only the stem remaining studded.
In the Czech Republic nowadays the ovens are gasfired, but glassblowing still remains a very labour intensive undertaking. 
Som glasses require teamwork, with one artisan blowing the glass, while his collegue adds the decoration.

If you look under the foot of the glass, you will see the circular mark left by the blowing iron. Though most glasses are blown, sometimes moulds are used to give them a special twist or angled design.
It goes without saying that only a true craftsman masters the technique of authentic historical reproduction. This, in turn, limits production to 20-30 glasses per day.

The art of glassblowing is passed on from father to son over the generations, with each family jealously guarding its secrets.