Well, in a nutshell, yes. These crystals form from tartaric acid that overtime ‘fall out’ of the wine and are called "tartrates". Their presence does not mean there is something faulty or wrong with the wine – in fact we feel it is quite the opposite.
Briefly, tartaric acid is the predominant natural, harmless acid in grapes and subsequent wine. It plays a vital role in the stability, pH, colour, structure and taste of finished wine.
A part of tartaric acid’s solubility is temperature dependent, as such when a wine is chilled for an extended period, the unstable form of tartaric acid will "crystallise" and precipitate out creating crystal deposits or ‘tartrates’. These tartrates often capture varying levels of colour and tannins in them.
During the aging process in the barrel a portion of the unstable tartrates precipitate out binding to the walls of the barrel. Once emptied, the barrels are steamed and /or washed to remove the tartrates and lees, although some remain dissolved in the wine and may precipitate out later in the bottle over time forming what often is referred to as a "crust".
So why do not all red wines have these crystals? Well some may be too ‘young’ and not enough time has elapsed for the crystals to form, or the conditions have not been conducive, or maybe the wine has minimal unstable tartaric acid remaining at the time of bottling due to the variety or season. Alternatively, some wineries may, for aesthetics, decide to remove all crystals through a process known as cold stabilisation. Prior to bottling, the wine in question is chilled to a sub zero temperature for a prescribed period to force the unstable tartrates to precipitate.
What about Smidge Wines? As a specialist winery, handcrafting wine of extraordinary quality in small quantities we view the presence of tartrates as showcasing our winemaking philosophy in action.
We believe that each intervention and action we make throughout the journey of every wine is done balancing the risk of action against the benefit to quality, flavour & stability. We view that no matter how carefully it can be done, artificially cold stabilising will change pH and acidity, and independent of the number of trials that can be done, it risks having some influence on the balance, structure, hue and flavour of a final wine. Sometimes these changes can be subtle, other times more noticeable.
We prefer to avoid this risk, and allow these interactions to occur naturally in the bottle over a number of years. So to answer the question – yes, we think these crystals are definitely diamonds!