Articles
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 […]
Yeast nutrition and successful fermentations
Introduction Successful primary fermentations of grape juice depend upon a number of factors: nutritional aspects are of critical interest as more becomes known about the nutritional needs of yeast. The following article discusses some of the relevant issues in regard to yeast nutrition in fermentations. Nutrients A number of different nutrient types are necessary for […]
Yeast based wine additives – Are the many claims made about these products justified?
Introduction There are a number of products made from Inactive Dry Yeast (IDY) that are used in various ways in modern winemaking. Many claims are made about their properties and benefits, however not all these claims have been scientifically proven leading to some confusion amongst winemakers. This article looks at the proven benefits of these […]
Wine analysis during crushing and pressing
Introduction There are a number of different tests that are done on juice and must at the time of crushing and pressing. These tests are explained below with some new developments in tests and equipment noted. Testing during crushing and pressing The main analyses performed during the process of crushing and pressing grapes are well […]
Mannoproteins – How are they used in winemaking?
Introduction Mannoproteins are a naturally occurring group of proteins found in the cell walls of yeasts. In particular, the mannoproteins in the wine yeast Saccharomyces cerevisiae have been studied extensively. The beneficial winemaking properties of mannoproteins, including tartrate stabilisation, are discussed in this article. Properties of mannoproteins It has been observed for many years that […]
Is the drinking water at your winery safe to drink?
Introduction Laboratory testing for a winery usually is thought of as dealing only with wine, but there is another important liquid that should be tested regularly – your drinking water. If your winery is not on “town water”, that is if you use tank water for drinking water then you may be risking the health […]
Alcohol and Standard Drinks Statements
June 2013 Introduction The accurate measurement of alcohol in wine is relatively easy for experienced laboratory operators with the correct equipment and techniques. The use of this measurement on labels, however, is a regulatory minefield. In this article we discuss the best technique to measure alcohol and the best way to use the data correctly. […]
Nitrogen compounds and supplements
January 2013 Introduction Yeasts have a strict need for nitrogenous compounds during fermentation of grape juice. Most grape must is deficient in nitrogen and so supplements are normally added to increase the level of nitrogen compounds in the must. By having a sufficient level of nitrogen, the yeast can ferment the must to dryness with […]
