When can I add water to facilitate fermentation?

Exporter News | March 2021
11 Mar 2021
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Australia has well-defined rules regarding the addition of water to grape juice and must. Clause 5(7C) of Standard 4.5.1) of the Australia New Zealand Food Standards Code (Code) provides that:

‘Water may only be added to wine, sparkling wine and fortified wine to facilitate fermentation if the water is added to dilute the high sugar grape must prior to fermentation and does not dilute the must below 13.5 degrees Bé.’

Wine Australia is often asked how to record such additions and another common question concerns the timing of any water addition.

The Code states the addition should be ‘prior to fermentation’ and, read strictly, this could be interpreted as prohibiting the addition of water in circumstances where fermentation had started spontaneously – for example, in a picking bin prior to being delivered to the winery. Considering such strict interpretation is not in keeping with the objective of the Code,  Wine Australia’s advice  is that water can be added to must or juice irrespective of whether fermentation has technically started, provided the Baumé is not lower than 13.5 degrees and the addition does not result in a Baumé below the 13.5 threshold.

Hence, we require three items to be recorded in order to ensure compliance with the Code:

  • the identity of each product treated with extraneous water at the must stage
  • the Baumé of the must before and after the water is added, and
  • the change in volume resulting from the addition.

What about LSJ?

There is no similar restriction on the timing of low-sugar juice (LSJ) additions during the winemaking process.

However, keep in mind that LSJ addition should be treated as a blending operation, not an addition. This is because the legitimacy of LSJ use is determined by the definition of wine:

‘Wine means the product of the complete or partial fermentation of fresh grapes, or a mixture of that product and products derived solely from grapes.’

So, for example, if a product had 16 per cent LSJ from Shiraz blended into 84 per cent Cabernet wine, the result would no longer be entitled to a single variety claim. It could be described as a Cabernet Shiraz (or a non-varietal wine). Alternatively, adding extraneous water to Shiraz, for example, would not dilute its credentials as a Shiraz. The restriction is not on the added volume, but on the timing of the addition (i.e. to must >13.5° Baumé).

The Australian Wine and Research Institute (AWRI) maintains a series of excellent online calculators on its website, including one that calculates the amount of water you can lawfully add based on the original Baume concentration of your juice or must prior to fermentation. You can access the calculator tool here.


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This content is restricted to wine exporters and levy-payers. Some reports are available for purchase to non-levy payers/exporters.