Wine Diamonds: The Sparkle You Didn’t Expect

If you’ve ever spotted tiny crystals at the bottom of your wine bottle or clinging to the cork, you might have had a moment of panic - is that glass? The good news is, it’s not. Those little gems are what we fondly call wine diamonds - and they’re a completely natural, harmless part of winemaking.

So, what exactly are wine diamonds?
Wine diamonds (the scientific term is tartrate crystals) are formed from tartaric acid - one of the natural acids found in grapes. During winemaking, tartaric acid sometimes binds with potassium and precipitates out of the wine as potassium bitartrate. When that happens, tiny crystals form that can look like grains of sugar or shards of glass at the bottom of your glass or bottle.

They’re completely safe, tasteless, and even edible (cream of tartar - yes, the baking ingredient - is made from the same stuff!).

Why do they form?
Temperature plays the biggest role. Just like sugar dissolves better in hot tea than iced tea, tartaric acid stays dissolved in warmer wine but can crystallise and fall out of solution when the wine gets cold.

That means if your wine has been stored in the fridge or experienced a sudden drop in temperature (especially for extended periods), those crystals might form naturally over time. It’s simply chemistry at work - not a fault or contamination.

Which wines are more likely to have them?
Wine diamonds most often appear in:
•    White wines, varieties like Riesling and Chardonnay, because they’re typically chilled before drinking and generally have higher natural amounts of tartaric acid in the grapes.
•    Unfined or minimally filtered wines, where winemakers prefer to keep the wine as natural and unprocessed as possible.
•    Wines stored in cooler conditions for long periods, including the fridge or a cold cellar.

So if you find them in your bottle of Bec Hardy Riesling, take it as a compliment - it’s a sign the wine has been made gently, with minimal intervention, and hasn’t been over-processed to strip out every last trace of nature.

Can they be prevented?
Winemakers can remove tartarates by a process called cold stabilisation, where the wine is deliberately chilled before bottling to force the crystals to form and fall out early. However, that process can also slightly alter the wine’s flavour - and at Bec Hardy, we prefer to keep our wines as pure and expressive as possible.

The bottom line
If you spot wine diamonds in your bottle, there’s no need to worry - or to pour the wine away! They’re simply a natural by-product of winemaking.

Think of them as a little sparkle from the vineyard - a reminder that wine is a living, natural product that continues to evolve even in the bottle.

So next time you see those glittering crystals, raise your glass (diamonds and all) to nature’s handiwork.