torsdag 14. august 2014

Krystallglass

Image courtesy of meawpong 3405 / FreeDigitalPhotos.net

Jeg har tidligere skrytt av glassets egenskaper i forhold til plast. Dette gjelder imidlertid bare for helt vanlig, billig glass. Krystallglass, derimot, spesielt av eldre type kan ha et høyt innhold av bly som faktisk kan lekke ut i glasset hvis innholdet blir stående i lengre tid. Det er nok rimelig trygt å bruke krystallglass i et fint middagsselskap, men å ha f.eks portvin stående i lengre tid i en krystallkaraffel er en helt annen sak. Dette var nok mer vanlig før i tiden, og da spesielt i finere kretser i befolkningen, så jeg tror ikke det er den helt store trusselen for oss i dagens samfunn. Men skulle du ha en gammel tante som tilbyr deg portvin fra en krystallkaraffel som hun drar frem ved festlige anledninger så tror jeg at jeg ville takket nei. Under her kan du lese hvorfor. Dette er sakset fra wikipedia.

Leaded crystal wineglasses and decanters are generally not considered to pose a significant health risk, provided that these items are washed thoroughly before use, that beverages are not stored in these containers for more than a few hours, and provided that they are not used by children.
It has been proposed that the historic association of gout with the upper classes in Europe and America was, in part, caused by their extensive use of lead crystal decanters to store fortified wines and whisky. Lin et al. have statistical evidence linking gout to lead poisoning.
Items made of lead glass may leach lead into the food and beverages contained. In a study performed at North Carolina State University,the amount of lead migration was measured for port wine stored in lead crystal decanters. After two days, lead levels were 89 µg/L (micrograms per liter). After four months, lead levels were between 2,000 and 5,000 µg/L. White wine doubled its lead content within an hour of storage and tripled it within four hours. Some brandy stored in lead crystal for over five years had lead levels around 20,000 µg/L. To put this into perspective, the U.S. Environmental Protection Agency's lead standard for drinking water is 15 µg/L = 0.015 parts per million. Citrus juices and other acidic drinks leach lead from crystal as effectively as alcoholic beverages. Under conditions of repeated use of the decanter, the lead leaching steeply decreases with increasing use. This finding is "consistent with ceramic chemistry theory, which predicts that leaching of Pb from crystal is self-limiting exponentially as a function of increasing distance from the crystal-liquid interface." Lead leaching still occurs, but the quantity that leaches into a glass of wine or other beverage let stand for a few hours is much smaller than the quantity of lead consumed daily in ordinary diet. An ordinary diet contains about 70 µg of lead per day.

Noe å tenke på for dem som blir skikkelig fristet til å kjøpe krystallglass når de er på ferie i øst-Europa der man ofte kan gjøre gode kupp. Kanskje det er bedre å kjøpe noe til pynt i krystall istedet for drikkeglass?