The Glamour of a Crystal Decanter :: but please don't use them as they were intended...
If, like me, you have a soft spot for the glint and glamour
of a beautifully cut crystal decanter,
you may want to think twice about using them as they
were actually intended.
Because with potentially high levels of lead contained within the crystal,
that innocuous-looking decanter can leach lead into the alcohol,
creating a dangerous drink.
Oh, but you say, surely modern crystal doesn't still contain
lead in dangerous quantities?
Well, sadly, yes, much of it does,
because adding lead oxide gives glass a higher refractive index
(or higher shine).
But it's not all doom and gloom,
because it takes several hours for the lead to leach into alcohol
in discernible levels,
so drinking from lead crystal glassware is fine,
and using lead crystal decanters to serve wine or spirits
is also fine, as long as it consumed within a few hours.
The problems arise when people store spirits, like brandy or whisky,
in lead crystal decanters which live on the now-fashionable bar cart.
And as the weeks tick by, so does the lead transfer.
What's the difference between crystal and glass?
Technically, there really is no such thing as lead crystal,
because glass, by it's solid nature, is not crystalline.
But the word has been used historically to describe the brilliant shine
of glass to which lead has been added at the melt stage.
Why is Lead used in Crystal then?
As well as raising the refractive index of the glass,
the addition of lead oxide makes it heavier,
increases the dispersion level
(meaning the degree to which an object
separates light into a spectra, or how much it sparkles like a prism),
and decreases its viscosity.
That allows it to be worked at a lower temperature,
and makes it easier to remove bubbles (i.e. make it flawless).
It is this last quality which is perhaps the most important,
allowing lead crystal to be almost flawless and perfectly clear.
It's also the reason why a lead crystal glass will make that characteristic
"ringing" sound, whereas a cheaper glass one will not.
In a lead crystal glass, the potassium ions are bound very tightly,
(thus the weight)
so when struck, the lead crystal will absorb more energy
and oscillate as a result: making that ringing sound.
Far from an old wives tale, this one has science to back it up!
Is lead crystal glass old or new?
The oldest lead glass known was found in Mesopotamia,
which is believed to be where glass was first invented.
A fragment dated to be from 1400 BC had a small amount of lead present.
It's not known whether that was added, or naturally present.
Lead glass, dating back to 200 BC, has also been found in China,
and it is believed that lead oxide was added
during glass production to create a jade substitute.
During the Middle Ages in Europe, lead was used to create coloured glass
to imitate precious stones.
Both the glass and texts describing its production
survive from this time.
In more modern times, the production of clear lead crystal glassware
is mostly linked to George Ravenscroft (1618-1681),
an early industrialist whose factories produced such high quality clear crystal
that England became the centre of glass production
in the 18th and 19th centuries,
taking the title from Venice and Bohemia.
At that time, lead crystal glass was taxed by weight not volume,
so manufacturers responded by making hollow stems,
smaller glasses, and incorporating elaborate cut patterns on it.
(A marvellous example of ingenuity resulting in a more beautiful product!)
Modern Lead Crystal
These days, crystal glass may or may not contain lead.
In the European Union, glassware may only be labelled "lead crystal"
if it contains at least 24% of lead oxide.
Glassware with less lead oxide, or made with lead substitutes
(such as barium oxide, zinc oxide or potassium oxide
and referred to as lead-free)
must be labelled "crystallin" or "crystal glass".
Lead free crystal is much lighter than lead crystal,
with less dispersive (the sparkle factor) qualities,
but it can have a similar refractive (shine) index.
Meaning, it's not quite as sparkly, but it's pretty good.
Should I throw out all my lead crystal decanters then?
No, don't throw them out!
And that is the point of my post : use them not as they were intended
(i.e. to store alcohol for a length of time)
but use them instead as a collection of sparkly beautiful shapes.
Fill them just before you use them,
and store them in groups with nothing but air (or coloured water) in them.
They will still be items of beauty,
with a fascinatingly old history,
but they won't cause anybody any harm.