Revolutionary new product for tartrate stabilisation

Karien O'Kennedy - 01 Aug 2017

A new product containing the active ingredient potassium poly-aspartate (KPA) will be on the market soon. It has been legalised by the OIV for use to prevent tartrate crystal formation in white and red wines.

The contribution of lactic acid bacteria to the sensorial characteristics of red wine

Hélène Nieuwoudt - 06 Apr 2017

The results of the research clearly indicate that lactic acid bacterial strains may impact significantly on the aroma and flavour of wine. The results of the study are important to the wine industry because they illustrate and emphasise the potential contribution of different MLF cultures to wine aroma and flavour, and the potential to influence consumer preferences.

Reviewing YAN and Hydrogen Sulfide: Part 2

Denise Gardner - 09 Feb 2017

One of the main arguments for avoiding “sulfur” as a description term for an aroma is due to the fact that there are actually several forms of aromatic sulfur-containing compounds found in wine, and they can have very different aromas (smells, odors) associated with that one compound.

Reviewing YAN and Hydrogen Sulfide: Part 1

Denise Gardner - 09 Feb 2017

The variability associated with YAN provides a challenge to winemakers: the lack of predictability associated with hydrogen sulfide formation during primary fermentation due to unfulfilled nitrogen needs by wine yeasts.

What are volatile thiols?

Avery Heelan - 24 Nov 2016

Volatile thiols are most prevalent in Sauvignon blanc, specifically New Zealand style, giving it the distinctive aroma profile which has given designation and respect to this variety and grape growing region. The volatile thiols responsible for these aromas include 4MMP, 3MH and 3MHA. 

Polyaspartate to avoid tartrate precipitation

stabiWine - 18 Aug 2016

The technological, economic and environmental characteristics of PAA are providing very significant advantages on all present practices. Once authorized, tartaric stabilization through addition of PAA is expected to become the first choice for a very large number of wine producers in Europe, especially among small and medium size facilities.

Development of sulfur off-odors post-fermentation

James Osborne - 15 Jul 2016

While H2S formation occurs mainly during primary fermentation, additional volatile sulfur compounds can be formed at later stages during winemaking. The formation of these compounds can be difficult to predict, and their formation is not necessarily related to H2S issues during the primary fermentation.

Top tips for filtration

Matt Holdstock - 11 Jul 2016

Matt Holdstock, a senior oenologist at the AWRI,  shares his top 8 tips / factors to keep in mind when considering filtration of wine.

New detection technology may yield a TCA-free future for cork suppliers

By Mary Ellen Shoup - 20 Jun 2016

Wine cork quality control has hit a new level of precision with cork producer Amorim’s NDtech, an automated system that screens individual cork stoppers on the production line for trichloroanisole (TCA). 

The choice of bottle closures

Charl Theron in WineLand Magazine - 09 Jun 2016

Irrespective of the responsibility for the packaging the combination of the wine, container and the closure of the container must be executed optimally to ensure that the wine reaches the consumer in the best condition. The choice of the bottle closure is only one of the decisive factors.

Enhancement of Sauvignon blanc wine through yeast combinations

by Hentie Swiegers, Ellie King, Brooke Travis, Leigh Francis & Sakkie Pretorius - 09 Jun 2016

In this study it is clear that yeast combinations are potentially a powerful mechanism to increase fruitiness in white wines, thereby increasing the wine’s consumer appeal.

Article published in 2007 in Wineland Magazine

How higher alcohols and volatile phenols impact on key aromas

Russell Moss - 23 May 2016

When the winemaker typically thinks of volatile phenols, usually the first compounds to come to mind are 4-EP and 4-EG, which produce an unpleasant “band-aid”- or “barnyard”-like aroma. However, there are volatile phenols which are intrinsic to the aroma of some wines, such is the case with 4-vinylphenol/4-vinylguiacol which provide Gewürztraminer with a carnation and clove-like aroma.

Oxygen permeating through oak barrels – new results

by Wessel du Toit in WineLand Magazine - 16 May 2016

Recent advances in measuring oxygen in a non-destructive way has led the way for more real-time measurements. This technology uses a principle where oxygen concentrations can be measured inside a bottle, tank or barrel without opening these containers. Eight of these oxygen sensors were placed at locations inside four new fine grain French, five new, fine grain American oak and four new medium grain American oak barrels which were filled with model wine. This model wine consisted of only 15% ethanol at a pH of 3.5 of which the oxygen was previously removed. This was done in order to measure the oxygen transfer more accurately, as no anti-oxidants were present in this model wine which could have reacted with the oxygen as would happen in real wine.

The causes of protein instability in white wine

Karien O'Kennedy - 29 Apr 2016

Recently various alternatives were identified, the most promising of which appears to be the protease, Proctase. This article provides a short overview of the proteins responsible for instability, as well as the factors that impact on their stability.

ORAL BACTERIA SHOWN TO PRODUCE AROMATIC VOLATILES FROM GLYCOSIDIC PRECURSORS

Becca Yeamans, (www.academicwino.com) - 22 Apr 2016

A 2015 study in the journal Food Chemistry aimed to evaluate whether or not human oral microbiota can convert odorless aromatic precursor compounds in wine into their corresponding aromatic glycosidic compounds. The results could potentially have a profound impact on our understanding of how we taste and evaluate wines.

RESCUING MINERALITY

Jamie Goode (published October 2014) - 22 Apr 2016

"Wines that smell 'mineral' tend to be white wines, and the source of this matchstick/mineral character is most likely a volatile sulfur compound produced during fermentation by yeasts."

Brettanomyces – the yeast lurking in your wine

by Marli Louw, Maret du Toit & Benoit Divol in WineLand Magazine - 11 Apr 2016

Most winemakers know the feared five-letter word “Brett” all too well. Brettanomyces bruxellensis is a famous red wine spoilage yeast, responsible for financial losses within the wine industry yearly. Research has allowed significant advances in our global understanding of B. bruxellensis, especially concerning this yeast’s peculiar ability to survive and develop in a matrix as harsh as wine. This article provides an overview of these recent research findings.

BALANCE AND COMPLEXITY: HOW OXYGEN AND AROMATIC INTERACTIONS IMPACT WINE

by Remy Charest - Nomacorc - 11 Apr 2016

The emergence of a complex bouquet has a lot to do with the presence of many different components in the wine itself, of course, but it also is shaped by the way these compounds interact. Certain compounds act as boosters for others, making them more easily perceptible.

Pectin test protocol

Practical guidelines by Karien O'Kennedy - 05 Apr 2016

The use of enzymes in winemaking is common practice today. There is a wide variety of pectinase based enzymes available to winemakers. Quality and efficacy differences exist and performing a pectin test is one way to establish the efficacy of a particular enzyme, especially when fast depectinisation before flotation is the objective.  

The use of exogenous tannins in winemaking

Karien O’Kennedy - 05 Apr 2016

A wide variety of tannins are available from different suppliers. Even bigger than the variety of trade names are the differences in quality of all the products. These differences in quality are as a result of the origin and the manufacturing process of the tannins. Tannins extracted from grape seeds and grape skins are usually the most expensive, followed by tannins from oak wood. It usually also is the more expensive tannins that are the most effective. It is extremely important that wine cellars make very sure that the tannins they are using have the desired effect.

Malo now BEFORE alcoholic fermentation

Karien O'Kennedy - 05 Apr 2016

A born and bred South African bacterium is making headlines and winning awards for bringing about a complete paradigm shift in the way we go about malolactic fermentation. First there was spontaneous, which is now considered “so yesterday”. Then came commercial cultures to be inoculated after alcoholic fermentation (AF), offering various advantageous over spontaneous such as low VA, low or no biogenic amines, speed, etc. The past few years were dominated by AF/MLF co-inoculation offering further advantageous such as even faster speed, reliability and aroma contributions.

BUT now Danish biotechnology company Chr. Hansen has launched Viniflora NoVA™ - a Lactobacillus plantarum culture that can complete MLF in as fast as three days before AF!

Metabolomics: New Techniques to Find out The Hidden Secrets of Wines

by Remy Charest - Nomacorc - 02 Mar 2016

Thanks to science, we know more and more about what is going on in a wine as it’s taking shape in the cellar or evolving in bottles. But as French researcher Régis Gougeon has been finding out, we’ve only seen the tip of the iceberg.

The scientific puzzle that is rotundone

Wine Australia: Research and Development - 13 Dec 2015

Since 2007, when an AWRI team revealed that rotundone found in grape skins is responsible for the distinctive black pepper flavours in many Shiraz wines, scientists have been working to understand the factors that influence its presence and potency. However, each new discovery brings new questions.

Metals in wine is a complicated story

Wine Australia: Research and Development - 13 Dec 2015

Research has discovered that adding a little copper to white wine prior to bottling ‘just in case’ is usually ineffective and can actually be counterproductive.

"Free" doesn't always mean free - rethinking SO2 measurements in the winery

Gavin L. Sacks and Patricia A. Howe, Research Focus - Cornell University - 02 Dec 2015

Researchers at Cornell University have developed a simple, inexpensive headspace – gas detection tube (HS-GDT) method that accurately measures molecular SO2 in red wines. All standard approaches to free SO2 badly overestimate the amount of free and molecular SO2 in all wines (particularly red wines) due to the presence of weak binders like anthocyanins.

Grape seed color not helpful in assessing wine tannins

By Scott Weybright, College of Agricultural, Human & Natural Resource Sciences - 18 Nov 2015

PROSSER, Wash. – For decades, if not centuries, the changing color of a grape’s seed has played a role in determining when winemakers harvest grapes. After some complex experiments, though, researchers at Washington State University have determined that seed colors don’t have the long-held impact, contrary to wine mythology.

Sustainable Winemaking

by Jackson Family Wines - 05 Nov 2015

Professor Roger Boulton explains the water and energy saving features that contribute to sustainable winemaking at the UC Davis Teaching and Research Winery in a video provided by Jackson Family Wines.

source:https://vimeo.com/user17673657/review/144404028/894f700122

Secretion of hydrolytic enzymes by non-Saccharomyces yeasts – a relevant trait for winemaking?

by Benoit Divol & Mathabatha Setati - 30 Oct 2015

The secretion of hydrolytic enzymes (e.g. proteases, glycosidases and pectinases) is known to be much stronger in non-Saccharomyces yeasts than in S. cerevisiae. This trait has been reported repeatedly in literature and identified as one of the main contributions of non-Saccharomyces yeasts. The aim of the current study was to screen a large collection of non-Saccharomyces yeasts for pectinase, β-glucosidase and protease activity all at pH 3.5 and to test the actual secretion of hydrolytic enzymes during fermentation of synthetic grape juice.

Polyphenols in wine

by Jamie Goode - 18 Oct 2015

Polyphenols are a large group of compounds that use a chemical structure called phenol as the basic building block. That’s where the name comes from: ‘poly’ phenols are where more than one phenol group is joined to another. They are probably the most important group of flavour chemicals in red wines, but are of much less importance in whites.

A guide to the fining of wine

by James F. Harbertson, Washington State University - 13 Oct 2015

Wine is a product of both the vineyard and the techniques the winemaker uses. Occasionally, aspects of the wine need to be refined more dramatically than can be dealt with by field adjustments or simple blending because not every growing season or fermentation goes the way the winemaker wants. Fining is a technique that is used to remove unwanted juice/wine components that affect clarification, astringency, color, bitterness, and aroma; the technique works for both red and white winemaking.

HOW QUICKLY DOES OXYGEN DISAPPEAR FROM WHITE WINE?

by Wessel du Toit, Daniella Fracassetti, Carien Coetzee, Andreja Vanzo & Davide Ballabio in WineLand Magazine - 12 Oct 2015

Oxygen plays an important role in wine production. In general the addition of oxygen in white wine is not wanted. This is due to the development of a brown colour, a decrease in fruitiness in the wines and an increase in acetaldehyde levels. 

Image: www.winemag.com

 

Dissolved Oxygen and Free SO2

Nicky Wilton - Vinlab - 04 Oct 2015

Oxygen contact with wine during processing is nearly always unavoidable. Unfortunately, oxygen exposure is not always desirable. Many clients complain of an SO2 imbalance i.e. low free SO2 levels together with high total SO2 levels. The culprit in these cases is usually too much dissolved oxygen.

Local Microbes Give Wine Character

Article review by Ruth Williams in TheScientist / Image: Vineyard in New Zealand by Matt Goddard - 26 Sep 2015

The distinct regional conditions, or terroir, in which grapes are grown are thought to shape a wine’s character. But strict scientific evidence of this phenomenon has been lacking. Now, researchers in Auckland, New Zealand, have confirmed that at least one aspect of terroir—local differences in yeast strains—does indeed alter the outcome of Sauvignon Blanc fermentation. Their findings were published today (September 24) in Scientific Reports.

Like grilling a steak, but much slower: How the Maillard Reaction affects the aromas of wine

by Remy Charest - Nomarcorc blog - 18 Sep 2015

In the world of food and wine pairings, nothing is more classic than matching a nice piece of grilled meat with a big red wine like Bordeaux. The two work well together, partly due to the counterpoint between the meaty flavors and the fruity character of the wine and the way the fat in the meat softens the tannins, but also because they share a number of aromatic components that come from the same source: the Maillard reaction.

The Bubbles: Basics about sparkling wine production techniques

By Denise M. Gardner, Wine & Grape U. - 18 Sep 2015

There are several styles of sparkling wine that a winery should consider prior to making plans to incorporate a sparkling product into their wine portfolio.  To obtain a quality product, varietal selection and winery resources (i.e., funds, equipment, personnel, time availability) should be considered before undergoing production.

Influence of several oenological fining agents on ochratoxin A removal

Filipa Carvalho, António Inês, Fernando Milheiro Nunes, Luís Filipe-Ribeiro, Luís Abrunhosa, Fernanda Cosmea - Image: www.flickr.com - 17 Sep 2015

To evaluate their effectiveness, eleven commercial fining agents were used to get new approaches on OTA removal from wine.

How SO2 additions influence microbial diversity during fermentation

by Michael L. Swadener and David A. Mills in Practical Winery and Vineyard Journal, Wines and Vines September 2015 - 16 Sep 2015

The use of sulfur dioxide (sulfites or SO2) in winemaking is hardly a new technology-it has been used since the Romans started burning sulfur candles in emptied barrels to keep them from turning sour. The general antimicrobial and antioxidant effects of SO2 in wine have also been well known for several decades, and many modern winemakers find SO2 to be a key additive for producing (and preserving) premium quality wine.

Potential alternatives for bentonite

by Charl Theron in WineLand Magazine - 15 Sep 2015

The development of an effective, cheap alternative for bentonite has been researched intensively. Last year the use of the two enzymes, Aspergillopepsin I (A1) and Aspergillopepsin II (A2) was legalised in Australia and New Zealand. Both are proteolytic enzymes that can break down the proteins that cause turbidity in wine.

Breakthrough for analysis of volatile thiols in SA wines

by Wessel du Toit, Elizma van Wyngaard, Frederico Piano, Daniella Fracassetti, Marietjie Stander, Antonio Tirelli & Astrid Buica - 09 Sep 2015

Volatile thiols play an integral role in the passion fruit, grape fruit and guava aromas of different types of white wines. The Department of Viticulture and Oenology, Stellenbosch University, embarked on developing a new method for volatile thiol analysis in white wines, as well as to perform a screening to determine levels of these compounds in South African Sauvignon blanc wines.

Easy does it: Looking at barrel ageing practices with Nicolas Vivas

By Remy Charest - Nomarcorc Newsletter - 13 Aug 2015

Barrel aging is an important and valued part of winemaking, especially when producing longer-aging wines. The aging process has many potential benefits, starting with greater stability, especially in terms of the wines’ interaction with oxygen.

Best practices in malolactic fermentation (MLF) management

Article by Charl Theron, WineLand Magazine - 01 Jun 2015

Malolactic fermentation is an integrated part of winemaking which cannot be ignored. It can however be beneficial or detrimental and it is important that winemakers are well informed about it in order to make the right decisions. The execution of the decisions is also important to ensure that the required results are obtained in the wines.

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