Bottles of Fermented Soft Drinks

Following a Department of Health investigation, “a significant number” of fermented soft drinks have been found to contain alcohol levels above the allowed limits. The inquiry has brought important issues with re-fermentation at breweries to the forefront.

According to the Department of Health, the public is worried about the findings. Pregnant women and children, those who work jobs require a zero alcohol limit, people on prescription medication and those living in dry communities are of particular concern. The survey highlights the need for more intensive testing by brewers using the most up-to-date and advanced PCR tests and other beverage testing such as identifying Diastaticus (Saccharomyces cerevisiae diastaticus) contamination.

Concerning Findings

Sampling a range of fermented beverages from all over New South Wales, Tasmania, Victoria and Queensland, the Department found that 22.9% of kombucha samples had an alcohol content over the allowed limit of 1.15% abv, 36.7% of Kefir samples were above the permitted alcohol level and 9.8% of ginger beer samples were found to be over the limit.

As the Food Standards Australia New Zealand regulations, a fermented soft drink should have an ABV of less than 1.15%, the results were quite shocking. In fact, due to the large number of non-compliant results, the department brought in both industry and government stakeholders to discuss the problem. The results further highlighted issues with re-fermentation issues in alcoholic and non-alcoholic drinks alike.

“Heartbroken“ Brewers

After having to issue a recall of his product, the head brewer at Aether, Dave Ward said that they were “heartbroken” about the issues that had been highlighted with re-fermentation. Investigating the issue further, Ward suggested that wild yeast had contaminated the ginger beer, affecting the residual sugar levels. However, he said “that’s not what it appears to be… The three most common ways for re-fermentation to occur are dry hop creep; the presence of Diastaticus – a variant of Saccharomyces yeast which secretes an enzyme which in turn breaks down non-fermentable sugars into fermentable ones; or the presence of residual sugars from things like fruit which are added in.”

A Closer Look At The Causes Of Re-Fermentation

Stating “we’re still waiting on the lab results”, Ward went on to explain how each potential problem was dependent on a particular issue occurring. With the right beverage testing program in place, many of these issues can be avoided simply by monitoring the production process carefully and regular testing.

Ward stated “if you’ve got something that has residual sugars in it, and you want to keep those sugars in the product without the re-fermentation, then you either need to pasteurise or use sulphites, which inhibit yeast growth. They put the yeast to sleep effectively. You see it a lot in cider and alcoholic ginger beer.”

Talking about Diastaticus yeast, Ward said “quite often in a brewery they will run a house yeast strain and then a special one. If there’s cross-contamination of microorganisms it can cause re-fermentation.”

Again highlighting the need for regular testing, when asked about what the solution is, he said “Cleaning and also you can test for the presence of Diastaticus, using a PCR test (polymerase chain reaction), a piece of equipment that looks for the DNA fingerprint of Diastaticus. Most brewers won’t have a lab in-house, but they can use a third-party lab for testing (PCR test).”

Beverage Testing At Ferment

Brewing consultant Steve Henderson of Rockstar Brewing insisted that a good quality system was key for every brewery; “A brewery needs to have a good quality system, in the form of a quality manual – a document every brewer should have that sets out what your company stands for in respect to quality, determines what is tested for and things like dealing with customer complaints and recall procedures.” He continued to say “On the flip side, if you’re a brewery who tries to hide the fact that something’s gone wrong or deny it, people will be savvy and that will do more to damage the brand”.

Here at Ferment, we understand the need for fast, reliable and accurate testing. Our expert team offers a range of beverage testing options, including a PCR test for Diastaticus. Get in touch with our friendly beverage scientists today to find out more about how we can help you to ensure your product always meets the Food Standards Australia New Zealand regulations.

As well as our range of commercial testing services we also offer DIY test kits such as the high quality alcohol test kits.