Articles

Testing gives results

Greg Howell Vintessential Laboratories Introduction Some, but by no means all, samples we receive in our laboratories cause quite a bit of interest for us and quite some angst for our winemaker clients. These samples and how they are tested can present some interesting case studies in what can go wrong in the winemaking process. […]

Problem wines we've recently seen…

Greg Howell Introduction As a wine consulting laboratory business, now with labs in five States of Australia, we deal with many wineries and many thousands of wines every year. Most of these wines are of good quality; however a very small minority have some issues that need our help. Our job is to investigate what […]

Interwinery Analysis Group finds best test for sugars in wine

Carly Gamble and Greg Howell Introduction Determining the sugar content of juice and wine is an essential part of the winemaking process.  Glucose and fructose are the most abundant sugars naturally present in grapes and they are also fermentable sugars – their presence in finished wine leaving the wine susceptible to spoilage.  Accurate monitoring of […]

Safety considerations in your wine lab this vintage

Greg Howell Vintessential Laboratories Vintessential has built and opened three new wine testing laboratories in the past year – in Orange New South Wales, Hobart Tasmania and the Margaret River region of Western Australia. If our experience is any guide, your lab may be working outside the requirements of the appropriate Australian Standards! A winery […]

Acetaldehyde – how to limit its formation during fermentation

Steve Byrne and Greg Howell_x000D_ Vintessential Laboratories _x000D_ _x000D_ _x000D_ Introduction_x000D_ Although most winemakers are aware of acetaldehyde, it still causes some negative impacts on wine quality. It is the main carbonyl compound formed in wine during fermentation, although it can also be produced in wine via other mechanisms. High levels of this aldehyde can […]

Ethyl acetate – a misunderstood fermentation problem

Steve Byrne and Greg Howell _x000D_ _x000D_ Vintessential Laboratories _x000D_ _x000D_ Introduction_x000D_ 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 […]

Flotation for wine clarification – how does it work and why use it?

Greg Howell and Carly Gamble, Vintessential Laboratories _x000D_ _x000D_ Introduction_x000D_ 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 […]

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 […]

How to fix Stuck and Sluggish Fermentations

Stuck and sluggish fermentations can be a major concern during vintage and, in the worst cases, lead to irreversible wine spoilage. Problem fermentations are now better understood, which makes it possible to use prevention tools such as selected yeast strains, yeast hulls and winemaking practices. Restarting stuck ferments with Fermichamp yeast Stuck and sluggish fermentations […]

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_x000D_ 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 […]