Expert speakers educate and inspire

On 24 June 2019, winery owners, winemakers, students and industry professionals gathered at Denbies Wine Estate in Surrey for the first Wines of Great Britain (WineGB) Winemaking Technical Conference 2019.  

Organised by the membership organisation’s Winemaking Committee, a diverse line-up of speakers, an array of structured tastings, the chance to catch up with fellow producers and to network with important industry suppliers saw the event attract representatives from cellars of all sizes. The audience even included a group of Canadian winemakers from Brock University’s ‘Fizz Club’ who were on a grand tour of the UK. 

First on the conference programme was Dr Belinda Kemp, a senior research scientist at the Cool Climate Oenology and Viticulture Institute (CCOVI) at Brock University, Canada. Primarily looking at nitrogen and its role in the secondary fermentation, Belinda took delegates through her on-going research into what impact inorganic and organic nitrogen has on sugar consumption, bottle pressure and the chemical composition of sparkling wine during yeast acclimation. 

After analysing the amino acids and ammonia in the yeast nutrient products currently available on the market, including DAP, Fermaid O and Go-Ferm, four Chardonnay test wines had different nutrients added up until tirage. As the wine started with a yeast assimilable nitrogen (YAN) level of 67.2, which is enough for a base wine to go through secondary fermentation, a control wine was left with no additions.

“If you don’t know what your YAN levels are, you are potentially going to be adding things to the wine which you just don’t need and on a commercial scale, that will be costly,” said Belinda. “After rehydration, we looked at the nitrogen and what was happening to the viable yeast cell count. From the results of the first stage we saw that each of the wines got to the target sugar level, but the control took the longest. Then at the next stage, the control also took the longest, but all the wines were still healthy. The fastest through first and second ferment was the organic product, the Fermaid O. As the trial wines are still on lees, we don’t know what effect this will have on the final wine or the aromatics.” 

The study also looked at the sugar and the link between consumption and bottle pressure, showing that, despite what previous literature had recorded, this figure actually depends on the stage of the second fermentation and which nutrients have been used in the yeast acclimatisation. 

“In one treatment it took just 1g/l to reach 1bar but in others it took 5g/l to reach 1bar,” said Belinda. “The Fermaid O was again much quicker, while the inorganic products were much slower. We don’t know how important this link is but we are worried that Fermaid O might have an impact on the flavours and that because you have to add more of the product it will also have an impact on the overall biomass, which might cause gushing and issues for disgorging.”

Until the research team has conducted the sensory and chemical analysis on the finished wines, Belinda explained that it was difficult to say why, if you have sufficient YAN to begin with, you would want to add any nutrients at all.

Finally, Belinda touched on the Maillard Reaction and a new project she is working on to look at how specific amino acids and different sugars in sparkling wine behave to produce compounds which give caramel, toasty and nutty flavours.

“It is very challenging because no one has done any work on the Maillard Reaction in sparkling wine before,” said Belinda. “There are so many factors which affect it, from the grape variety, to the temperature and duration of storage, the levels of phenolic compounds and lipids, So2 and pressure. We think that in sparkling wine, acid also promotes the reaction, but it is very difficult to work out what is actually going on, so we are studying it.”

Improving quality without restricting innovation

A short break allowed delegates to network, meet key winery equipment and product suppliers, such as NP Seymour, Bruni Erben and Rankin Brothers and Sons, and view a range of over 20 ‘trouble free winemaking’ posters which had been developed by Plumpton College and covered topics such as mousy off flavour from LAB and Brettanomyces, the cause and effect of light strike, and acetic acid bacteria spoilage of wine and methods used to identify, control and prevent it. 

Returning to the Denbies Suite, chair of the WineGB Winemaking Committee, Emma Rice presented a talk on behalf of Peter Fera, looking at what the UK could learn, if anything, from South Africa’s Méthode Cap Classique (MCC) scheme for sparkling wine. 

After running through the history of the MMC scheme, how many producers are involved, how wines are classified and the overall rules, the presentation looked at the benefits of being involved. Essentially, while the uniquely South African name has found a loyal following in the domestic market, and the rules have raised quality, a lot of producers don’t care about the scheme and the international market remain largely unaware of it as a category. 

Therefore, when it comes to looking at the debate over whether or not ‘English Sparkling Wine’ needs a name, it was argued that “the overall name doesn’t help to sell wine and if you don’t have a serious marketing budget you will never get understanding from the consumer anyway”. Having experienced first-hand the benefits of using the term British wine abroad, Emma also suggested that producers would be best sticking to the status-quo. 

When it comes to regulation, Emma believes that a carefully managed open policy allows for innovation, such as the use of different varieties and methods like Charmat. New proposals are also currently being put forward for the PDO and PGI schemes as WineGB look to improve wine quality without restricting innovation. 

Following the unprecedented harvest of 2018, the group in charge of the schemes moved quickly to ensure that anyone who was over the 80hl/ha limits were not penalised, as high yield certainly did not correlate with low quality. While yield limits could not be scrapped entirely, DEFRA did agree to move to 135hl/ha. 

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