Pick up a glass with your eyes closed and you can tell more about it than you can by looking. The weight, and where the weight sits, is the whole story of how it was made.
Crystal is glass with something added to make it heavier, clearer and more refractive than ordinary soda glass. For 300 years that something was lead oxide, and a good crystal glass had a quarter of its weight in lead. It rang, it sparkled, and it leached. Ours is lead-free. The glasshouse in Portugal that makes Filo, Vela, Sera and Onda replaces the lead with barium and zinc oxides, which give the same clarity and most of the weight without the metal. It is the same crystal throughout the range. The differences between the four families are all in how it is shaped.
There are two ways to shape a glass, and both are in the catalogue.
The first is to blow it. A gather of molten crystal is taken from the furnace on the end of a hollow iron pipe, and the glassblower breathes into the pipe while turning it, so that the bubble grows evenly. The bubble is shaped against a wooden block, opened with tongs, and its lip is reheated and finished by hand. Every Vela carafe and every Filo wine glass is made this way. You can tell a mouth-blown piece by two things: the wall is thin and very slightly uneven, tapering towards the rim, and there is a faint spiral in the glass if you hold it to the window, left by the turning. The lip of a Vela carafe is pulled out by hand into a pouring spout, and no two are the same.
The second way is to press it. Molten crystal is dropped into a steel mould and a plunger forms the inside. Pressing gives a thick, even wall and a heavy base, and it gives the same shape every time, which is what you want in a tumbler that will be washed a thousand times. The Onda whisky tumbler is pressed. Its base is 28 mm of solid crystal and the whole glass weighs 380 g, which is why it sits on the table like a paperweight and stays where you put it. The ripple on the outside, the optic that gives Onda its name, is cut into the mould, so it is as crisp on the last glass of the run as the first.
A tumbler should be hard to knock over. A wine glass should be hard to notice.
That is the principle behind where the weight goes. A water or whisky tumbler carries its weight low, in the base, so it is stable in the hand and on the table. A wine glass carries almost no weight at all, because the wall has to be thin for the wine to show its colour and for the rim to disappear against the lip. A Filo wine glass weighs about 120 g, and most of that is in the foot.
The practical side. Thin mouth-blown glass is stronger than it looks, because the crystal is fully annealed, cooled slowly over hours so that there is no stress locked in the wall. But it is not made for the dishwasher. The heat and the detergent will dull it in a year. Wash a Vela or a Filo by hand in warm water with a soft cloth, and dry it while it is still warm with lint-free linen, holding it by the bowl rather than the stem. Pressed pieces, the Sera and Onda tumblers and jugs, take a gentle dishwasher cycle, and hand washing simply keeps them brilliant for longer.
A note on rings. Crystal does not need to be struck to be judged, but if you flick the rim of a Filo glass it will hold a note for a second or two. That is the sound of a fully fused, stress-free wall. A dull tick means a crack, or a glass that was cooled too fast. We check for it before anything leaves the glasshouse, and it is worth doing yourself when a parcel arrives.