You may have noticed some wine diamonds in our 2022 Riesling and thought they were glass shards or a flaw in the wine! Don’t panic, you’ve not found glass, you’ve found tartrate crystals or what winemakers sometimes term ‘wine diamonds’.
They don’t indicate that the wine is spoiled. Quite the opposite, in fact. Those harmless, tasteless jewels are called “wine diamonds,” and not because of their crystalline looks.
Wine diamonds are considered a sign of quality, at least in the eyes of some sommeliers and wine makers who say their presence indicates that a wine hasn’t been over-processed.
Wine diamonds aren’t diamonds, of course. They’re bits of potassium bitartrate — also referred to as potassium hydrogen tartrate or tartaric acid — and are a by-product of winemaking. Wine diamonds form during the fermentation process in either the bottles or in winery tanks when wine is stored at temperatures below 10 degrees Celsius.
Some winemakers use a process called cold stabilization to reduce the amount of wine diamonds in bottles. This involves chilling the wine while it sits in the fermentation tanks. Cold stabilization encourages the formation of crystals so they can be filtered out before bottling. But it’s not a guaranteed process as the crystals can still form in bottles if they are stored at cooler temperatures.
We aimed for minimal wine maker intervention with the 2022 Riesling not putting it through the cold stabilization process as it is an energy intensive process and doesn’t necessarily improve the quality of the wine. In fact some believe that stripping these tartrates out negatively affects the wine’s flavour and mouthfeel.
You can of course decant the last bit of the bottle or pour through a sieve, but we think if you are lucky enough to get the last glass from the bottle, smile, to yourself and count yourself lucky – you’ve found diamonds!