Articles
Ethyl acetate – a misunderstood fermentation problem
Steve Byrne and Greg Howell Vintessential Laboratories Introduction Ethyl acetate has long been associated with wine spoilage, imparting a distinct nail polish remover aroma to affected wine. Although a common taint, it has not traditionally been a very common test in our labs. One reason for this may be due to misconceptions about how it […]
Flotation for wine clarification – how does it work and why use it?
Greg Howell and Carly Gamble, Vintessential Laboratories Introduction The flotation process was originally developed in Australia and has been in use in the mining industry for over a century. It has been used in the wine industry for the clarification of juice for several decades and appears to be gaining renewed popularity due to recent […]
European trends in the use of mannoproteins
Introduction There has been a lot of research done recently on the use of mannoproteins in winemaking which has led to the release of several new products into the marketplace. These new products are making quite an impact on the sensory properties of sparkling, white and rosé wines. Mannoprotein products are being used in large […]
Co-inoculation: the latest great development in malolactic fermentation
Introduction Commercial strains of malolactic bacterial cultures have been available for many years. Until recently, these cultures were added after the completion of the alcoholic (yeast) fermentation. New research has enabled the development of strains of bacteria that can be added at the same time that yeast is added (co-inoculation). The advantages of co-inoculation are […]
Why wines with low Sugar-free extract are being rejected in China
Introduction Sugar-free extract is the latest unfamiliar expression to pass the lips of exporters of wine to China. This obscure test was the largest cause of wine being rejected by Chinese authorities last year (1). Below we discuss this test and make recommendations on what exporters should do to ensure that they have no technical […]
The Last Chance to Get Your Wine Right – Pre-Bottling Analysis
Introduction The wine you have made can be adjusted, fined, sulfured and played with for as long as you want. That is, until you lock it away in a bottle. So it’s important that the composition of your wine is exactly how you want it just prior to the bottling process. To be sure you […]
PCR – a new test in the battle against Brettanomyces spoilage yeast in wine
Introduction The molecular biology technique PCR has now been applied to the determination of Brettanomyces bruxellensis yeast in wine. A kit system is now available in Australia and has been used in our labs to determine the number of viable Brett yeast cells in wine with very good results. This is a rapid and very […]
My wine had low turbidity but still needed extensive filtering – why?
Introduction We often hear our winemaker customers complain “the wine had a turbidity of less than one NTU but the bottling company charged us extra for filtration!”. This extra filtering needed at bottling is often unexpected, but there are two tests that can be done to check the condition of the wine prior to sending […]
Another whack of the dragons tail: Problems with label sugar contents for China
Introduction As a wine export destination, China appears very attractive: a huge and growing middle class, increasing disposable income and an emerging interest in Western culture – such as wine. However, cracking the Middle Kingdom is not as easy as it seems. First a very low limit on manganese was announced early in 2014, and […]
Ebulliometry for measuring alcohol in wine: improve your accuracy
Introduction The following is an expanded version of the talk given by Steve Byrne at the Interwinery Analysis Group seminar in Adelaide on Friday 1 August 2014. The topic presented was ‘Advances in Ebulliometry and Tips for Improving Precision’. Background Ebulliometers have been used for measuring the alcoholic content of wine since the late-1800s. The […]
Over 23% of wines tested for export to China exceed the manganese limit!
Introduction Over 23% of the hundreds of wines we have tested for manganese recently are over the new limit imposed by China. This testing was recommended by Wine Australia in late February, for any wines exported to China because some wines have been over this limit and have been destroyed in China or returned to […]
Do you know what levels of trace metals are in your wine?
Introduction Wine contains a number of metal ions in very small, that is, trace amounts. These trace metals are generally harmless and in fact can be essential micro nutrients for humans. Most countries have legal limits on the level of certain trace metals in wine. The recent change in limits on manganese in China is […]
Winemaking with grapes affected by Botrytis cinerea
Botrytis cinerea is a weather driven fungus which causes the grapevine diseases botrytis bunch rot and grey mould. The ideal conditions of its development are humidity, high crop density, and important vegetation development with the following consequences: Poor juice yields. Low must nitrogen and vitamins content, due to the consumption by Botrytis cinerea for its […]
A simple and easy way to organise your lab for vintage
Introduction Prior to your busy vintage period, it’s important to be as organized as possible in your laboratory. One way to do this is to generate 3 main lists of what you require to effectively run your lab – we show you how below. By having all the tests you do documented as Test […]
Can petiole analysis help improve wine quality?
Introduction The time of year has come when the nutrient levels in grapevines are usually analysed. The article below explains the reason behind this widespread practice and how to avoid problems with testing, plus how this information can be used to help improve wine quality. Nutrients Like all plants, vines need certain nutrients to ensure […]
Why use enzymes in winemaking?
Enzymes are commonly used in winemaking. However, unlike yeast where the impact on the juice or must is easily observed and measured, the impact of enzymes is not so obvious. This article spells out the major applications of enzymes in winemaking and highlights the benefits of using these useful products. What are enzymes? Enzymes are naturally – occurring proteins. Each particular enzyme has a specific structure. […]
Is there too much residual copper in your wine?
The use of copper sulfate for fining in wine is well established and widely used. The level of residual copper is highly regulated and, yet, does not appear to be regularly checked by many winemakers. Based upon the results of our testing for residual copper this year, we outline why some caution is needed with this additive. Sulfide […]
Lets be clear about filtration
Introduction Filtration of wine is normally used as an important step in the final stages of winemaking to ensure clear and stable wine. Discussion of the types and sizes of microbes that can cause spoilage are included to demonstrate one of the main reasons for employing effective filtration. Some of the aspects of filtration are […]
Sparkling Wine: a peculiar lab sample
Introduction Sparkling wine is a bit of a strange substance to work with in a laboratory as it contains those pesky bubbles. Of course the bubbles are why we call it sparkling wine. But what exactly do we mean by ‘sparkling wine’? Sparkling wine – the Australian definition The definition actually varies from country to […]
Technical issues when using non-traditional wine packaging
Introduction There are numerous reasons why the use of traditional packaging for wine is changing. These can be for quality, environmental, cost or marketing reasons. Changing the form of the packaging can involve a number of technical challenges and problems, as the recent trend to screwcap bottles has demonstrated. In this article we look at […]
