Wine Faults and Flaws. Keith Grainger
technology of production since World War II have outstripped those of the previous 79 centuries. There have been huge changes in the methods and improvements in standards of viticulture, although the reliance upon chemical fertilisers, pesticides, and herbicides that began in the 1960s declined only recently and was certainly both damaging to the environment and wine quality. The recent advent of geolocating and remote and proximal sensing and soil mapping, so‐called ‘precision viticulture’, and techniques to determine the hydric stress of vines have enabled growers to fine tune site‐specific management practices, including the precise addition of desirable nutrients and, where permitted, measured quantities of adjusted irrigation water to individual vineyard blocks, or even precise parts of blocks.
In the winery there have been numerous advances in equipment design and quality, and winemaking procedures. Some of the most important of these are:
Grape sorting and selection systems to exclude unripe, rotten, or damaged fruit: spectacular innovations have been made in the technology of sorting equipment in the last 15 years, including the use of sophisticated optical sorters;
The widespread utilisation from the 1970s of temperature‐controlled fermentation vessels (usually constructed of easily cleanable AISI 316 or 304 grade stainless steel), although the move today is ‘back’ to vats made of wood or concrete;
Development of numerous individual strains of cultured yeasts aiding the control of fermentations and development of required flavours;
A detailed understanding of malolactic fermentation (MLF) and the development of suitable inoculums for use when deemed necessary;
The utilisation of a wider range of extraction techniques including pre‐fermentation cold soaks, rack, and return (délestage), flash détente and thermo détente;
The use of gases namely carbon dioxide, nitrogen, and argon, primarily to avoid unwanted oxidation;
The development of programmable enclosed pneumatic presses that can be gas‐flushed;
The utilisation of in‐tank micro‐oxygenation, particularly for inexpensive red wines, that helps polymerise long‐chain tannins and is a valuable tool if costly barrel ageing is not to take place;
Pre‐bottling cold stabilisation, often also using the ‘contact process’, to precipitate crystals of potassium bi‐tartrate or calcium tartrate. Alternatively, membrane electrodialysis may now be employed for this purpose;
The availability of systems employing membrane technology, for must and wine correction, and filtration, including front end microfiltration (MF), cross‐flow (tangential) MF, ultrafiltration (UF), reverse osmosis (RO), and pervaporation;
the improvement in cork closure quality, particularly regarding the cleansing of corks of 2,4,6‐trichloroanisole (TCA), and the introduction of effective alternative closures, including screw‐caps and synthetic closures with determined oxygen transmission rates (OTRs).
Of course, small‐ and medium‐scale producers, many of whom are focussed upon the individuality and quality of their wines, may choose not to utilise ‘advanced’ techniques in the vineyard or winery, including oenological additives, processing aids, or sophisticated (and expensive) technical equipment.
1.3 Changes in Markets and the Pattern of Wine Consumption in Recent Decades
The changes in the pattern of wine consumption of wine during the last 40 years have been dramatic. There has been spectacular growth in sales in many countries that have limited domestic production and accordingly rely upon imports to satisfy demand: for example, in the United Kingdom, per capita wine consumption rose from just 2 l in the early 1960s to 19.7 l in 2010–2016 [1]. In 2018, UK per capita consumption was approximately 24.6 l [2]. However, during the same period, the per capita consumption of many traditional European wine production countries declined by some 50%, albeit mostly of very low quality wines. Prior to the 1970s only 10% of all wines were exported from producing countries, including intra‐Europe ‘exports’; by 2016 over one‐third of wine consumed globally was produced in another country [1]. The journey undertaken to market wine in both bottle and bulk may be many thousands of miles, from the New World to the Old or vice versa, or from the West to the East. This massive rise in exports has only been possible because of the considerable improvements in the technical quality and particularly the stability of the product sold. ‘It's a great wine to drink locally but it doesn't travel’, an often heard expression when visiting wine regions in the 1970s and 1980s, is but a distant memory today. Microfiltration and ultrafiltration using membrane technology have been important tools in ensuring clarity and stability of the product, particularly in the case of the output of large producers. Other membrane processes, including reverse osmosis (RO) have enabled producers to achieve product of reasonably consistent quality and in styles that the marketers and gatekeepers believe to be popular with a wide audience, including those who were traditionally not wine drinkers.
Several ‘new’ markets have emerged in the last decades, particularly Asian countries: in the last few years, sales in China have surpassed the wine industry's expectations, especially for so‐called ‘fine’ wines, although, at the time of writing, this market has been contracting. The interest amongst wine lovers in the qualities and differences in styles in wines produced around the world is also high, as evidenced by the proliferation of wine societies and attendance at tutored tasting and other wine events, the growth in wine ‘tourism’, and the plethora of blogs and other Internet and media discussions. Annual global wine sales are estimated to amount to 246 million hectolitres, the equivalent of nearly 33 billion 75 cl bottles [3]. The diversity of retailers selling wine, declining for many years, has recently increased. The typical consumer of everyday wines is most likely to make their purchase in a supermarket rather than in a specialist outlet, but the Internet has been the salvation of independent merchants, providing a relatively inexpensive marketing vehicle and access to a national or even international customer base. Many of these outlets offer high quality wines from small, individualistic producers and, in some cases, the production operations are ‘crowd‐funded’ by enthusiastic and loyal customers.
The quality and style of wines from any region, or any producer, however small or large, will not be totally consistent from vintage to vintage – indeed it is these variations that makes individual wines so exciting to wine lovers. In other words, the quality properties of the finished product are not precisely predictable, unlike the product of other drink production technologies [4]. There is constant debate how much winemaking is considered to be an art or science. However, there is no doubt that the use of modern winemaking techniques has led to wines moving closer in style [5], and this is decried by both passionate small producers and serious and educated wine lovers. Certainly the use of technological equipment has led to less incidences of some faults and flaws but paradoxically has also contributed to the increase in others.
Although almost all ‘fine wines’ are bottled at source (usually at the winery but sometimes elsewhere in the region of production), there has been an increase in the last decade in shipping ‘everyday wines’ in bulk and bottling at destination. In fact this was commonplace until the 1970: cheaper wines were often transported in ‘SAFRAP’ (lined mild‐steel containers) or even ships' tanks, and of course wine had been transported in barrels for many centuries. The return to bulk shipping for inexpensive wines has been largely driven by economic factors, together with the need to be seen to reduce the environmental impact of transportation. There are other pros and cons to bulk transportation, particularly from a quality perspective. International Organization for Standardization (ISO) tanks and flexitanks are the two most widely used transport containers, and wines may become tainted from poorly maintained or cleaned ISO tanks, or the ethylene vinyl alcohol (EVOH) copolymer liner of flexitanks, although such instances are thankfully very rare. There are historic incidences of wines being tainted with naphthalene on journeys from Australia to Europe. Flexitanks may also permit some undesirable oxygen ingression, albeit at a very low level – the permeability of the material has decreased considerably since the 1990s. As flexitanks are generally ‘single‐use’, contamination