Guest blogger Emma Rice, from Custom Crush tells why she chose England to set up her wine business, and gives an insight into the analyses that are required in the process of creating English sparkling wines.
Wine Analysis and English Sparkling Wine
By Emma Rice at Custom Crush
Emma in her lab at Custom Crush HQ
I grew up in West Sussex and, via a vineyard in New Zealand, Oddbins, the London wine trade, Plumpton College, and wineries in Napa Valley and Tasmania, I found my way back here to set up Custom Crush UK Ltd in 2008.
My introduction to the local industry came earlier than I realised, when my mother confessed that I was parked in my pram at the end of a row of vines in Chilsdown Vineyard in West Dean whilst she picked grapes in the 1970s. Chilsdown no longer exists but the industry has seen a resurgence on a scale not dreamt of then.
I came back to the UK because I was excited about the possibilities and, having received my initial training here, it felt like a natural progression to come back from overseas and apply my newly honed skills closer to home. Custom Crush has several sides to it: wine analysis, winemaking consultancy, contract services and the sale of yeasts and other products from the Institut Oenologique de Champagne.
The laboratory, based in Chilgrove, near Chichester is now coming into its quiet period, having been rushed off our feet with pre-bottling work for the wineries making sparkling wine. Bottling for sparkling wine is different to bottling still wines in that we actively encourage yeast into the line – by its very nature it cannot be a sterile process. To avoid the need for two bottling lines in wineries where both still and sparkling wines are made it is often easier to call on the services of a contract bottler such as the IOC from Epernay. Organising the annual tour of the bottling lines and French engineers that accompany them can be daunting with lots of hilarious gesticulating and ‘Franglais’ spoken on all sides, but all has gone well this year bar a few minor hitches.
At the laboratory, at this stage of the winemaking process we aim to reassure the winemaker that the wines are ready for bottling and pinpoint any potential issues that may require treatment or, in the case of unfinished malolactic ferments, a little more patience.
WHY DO WINES NEED ANALYSING?
A typical pre-bottling analysis for sparkling wine will include the following: residual sugar, malic acid, total acidity, volatile acidity, free and total sulphur dioxide, pH and cold stability.
Residual Sugar – very important to establish how much, if any, sugar is left from the primary fermentation – the bottles can withstand about 6 bar of pressure after second fermentation – that comes from approximately 24g/L of sugar. If you merrily add 24g/L to a wine that has 3g/L already you run the risk of exploding bottles.
Malic Acid – if the wine has undergone MLF it is important to establish that it has finished before bottling to avoid complications in the bottle and potential off-flavours.
Total Acidity – to ensure the wine has enough acidity to carry it through the lees-ageing process; you cannot add acid but you may blend with another wine that is higher in acidity to bring up the total.
Volatile Acidity – there are legal limits for this, acetic acid is a natural by-product of fermentation but in larger quantities it is a fault. Good oxygen and SO2 management can help prevent it – it can only be rectified by blending out into another wine or by using expensive cross-flow filtration.
Free and Total SO2 – probably the most vital analysis tool at this stage. Too much SO2 and your wine will not ferment in bottle, too little and you run the risk of oxidation. Fine-tuning this is crucial.
pH – The pH of a wine has a major effect on the efficacy of the SO2 you add, if you add SO2 without knowing your pH you may as well do it blindfolded.
Cold Stability – this is not an exact science with sparkling wine prior to bottling – you will be changing the matrix again by adding yeast and sugar, but it is good practice to stabilise your wine for tartrates before bottling. This is an aesthetic issue rather than a true quality parameter. Once the wines leave your winery you have no control over how they are stored and if they are kept at low temperatures for extended periods they may throw a tartrate deposit. This is harmless but does cause problems at disgorging and supermarkets and retailers do not like to see crystals that look like glass in the bottles on their shelves.
Custom Crush has had two Australian winemakers working part-time over the last year; Alice is coming back for harvest. The core staff of Custom Crush is now Emma Rice, the founder, along with Jacob Leadley, a refugee from the City who graduated from Plumpton this summer and has taken to the mix of laboratory and winery work like a duck to water. We are looking forward to a very busy harvest.