A few days ago we were sitting around with some friends and I decided to open an Austrian Trockenbeerenauslese. As this was a fairly old and expensive wine, I made a few remarks about it and one friend, studying the bottle, remarked “No wonder it’s expensive, it’s got diamonds in it!”.
Well, these “diamonds” are of course not real “diamonds” and are also not that unusual in older, well crafted quality whites. These “diamonds”, or “crystals”, also known as “Wein Stein” (wine stones) in German, are in fact crystalized tartrates, specifically potassium-bitartrates.
So what does it mean when we see these wine diamonds in a bottle?
- – It tells you, among other things, that this wine was made from ripe grapes and the grapes had sufficient acidity and minerality for these crystals to form.
- – They are neither harmful nor a sign of poor quality (in the contrary)
We do not see these wine diamonds in North American or other New World wines very often as many whites are “cold stabilized”, a process whereby the wine is rapidly cooled to about -4C for up to 2 weeks in order for these types of crystals to “fall out” of the wine before it is bottled. Of course there is much debate about a process of brutalizing a wine in such a manner and the resulting change in taste and flavour.
Be that as it may, consider yourself lucky if you find some!
Keep the bottle upright for a while (possibly as long as a few days) in order for the crystals to settle to the bottom of the bottle; then pour carefully or decant.