Wares of Knutsford’s wide range of bottles includes clear wine bottles in the traditional Bordeaux shape – tall, straight sides with curved shoulders – in the standard 750ml wine bottle size. These are usually used for white or rose wine.
How clear glass wine bottles are filled
Everyone knows that wine is fermented grape juice, but how does it get from the vine into clear wine bottles?
Wine producers decide when the grapes are ready to harvest, as a rule, the riper the grape, the sweeter it is. Wine producers taste the grapes and use technical analysis to decide upon the best moment to gather in their fruit for the kind of wine they produce.
Northern hemisphere grapes are usually harvested from September – November, after which they are graded by quality according to the winemaker’s’ requirements.
Processing the grapes
White wine grapes then go through a destemming and crushing process to maximise the amount of juice released when they reach the pressing stage.
The grapes are then pressed to extract the juice, also called ‘must’. A finer juice comes from the most gentle pressing. The must then settles for a while to let any residues sink to the bottom so they can be removed. The must is then ready to be fermented.
This is the step that turns grape juice into wine, by converting the sugar content into alcohol. This is achieved through the action of yeast upon the sugar – either naturally derived form the vineyard or by adding cultured yeast. Each process works differently and must be carefully judged to achieve the correct result.
The vessel used for fermentation must also be carefully chosen – usually oak or stainless steel. Some wines, such as Chardonnay, are synonymous with oak barrel fermentation, while grapes with a sharper aroma such as Sauvignon Blanc or Riesling tend to be fermented in stainless steel.
The temperature is another critical factor, with white wines tending towards a cooler fermentation temperature than red.
In theory once all the sugar has become alcohol the fermentation process is complete, leaving a dry wine. If the winemaker is aiming for a sweeter wine the fermentation will be interrupted while some sugar remains, according to the degree of sweetness required. At this stage the dead yeast, called ‘lees’ can be drained off or left to age for a while, again according to taste.
Decanting to coloured or clear glass wine bottles
After a period of maturation, the wine can then be blended before being decanted into coloured or clear glass wine bottles. Traditionally, longer kept red wines are stored in coloured bottles will young drinking lighter wines are stored in clear bottles.