Implications of nitrogen nutrition for grapes, fermentation and wine

Abstract

This review discusses the impacts of nitrogen addition in the vineyard and winery, and establishes the effects that nitrogen has on grape berry and wine composition and the sensory attributes of wine. Nitrogen is the most abundant soil‐derived macronutrient in a grapevine, and plays a major role in many of the biological functions and processes of both grapevine and fermentative microorganisms. Manipulation of grapevine nitrogen nutrition has the potential to influence quality components in the grape and, ultimately, the wine. In addition, fermentation kinetics and formation of flavour‐active metabolites are also affected by the nitrogen status of the must, which can be further manipulated by addition of nitrogen in the winery. The only consistent effect of nitrogen application in the vineyard on grape berry quality components is an increase in the concentration of the major nitrogenous compounds, such as total nitrogen, total amino acids, arginine, proline and ammonium, and consequently yeast‐assimilable nitrogen (YAN). Both the form and amount of YAN have significant implications for wine quality. Low must YAN leads to low yeast populations and poor fermentation vigour, increased risk of sluggish/stuck/slow fermentations, increased production of undesirable thiols (e.g. hydrogen sulfide) and higher alcohols, and low production of esters and long chain volatile fatty acids. High must YAN leads to increased biomass and higher maximum heat output due to greater fermentation vigour, and increased formation of ethyl acetate, acetic acid and volatile acidity. Increased concentrations of haze‐causing proteins, urea and ethyl carbamate and biogenic amines are also associated with high YAN musts. The risk of microbial instability, potential taint from Botrytis‐infected fruit and possibly atypical ageing character is also increased. Intermediate must YAN favours the best balance between desirable and undesirable chemical and sensory wine attributes. ‘Macro tuning’, of berry nitrogen status can be achieved in the vineyard, given genetic constraints, but the final ‘micro tuning’ can be more readily achieved in the winery by the use of nitrogen supplements, such as diammonium phosphate (DAP) and the choice of fermentation conditions. This point highlights the need to monitor nitrogen not only in the vineyard but also in the must immediately before fermentation, so that appropriate additions can be made when required. Overall, optimisation of vineyard and fermentation nitrogen can contribute to quality factors in wine and hence affect its value. However, a better understanding of the effect of nitrogen on grape secondary metabolites and different types of nitrogen sources on yeast flavour metabolism and wine sensory properties is still required.

Amino Acids Profile of Two Galician White Grapevine Cultivars (Godello and Treixadura)

“…4%, 8.5 -19.1%, 5.1 -20.7% and 8.3 -11.9% of the total amino acids present in grapes, depending on the cultivar and vintage. Arginine has been pointed out as the most abundant amino acids in grapes (Bell and Henschke, 2005), in accordance with our findings.…”

Produtividade e composição de uva e de vinho de videiras consorciadas com plantas de cobertura

“…Produtividade e teores de N amoniacal e total, de uva coletada nos estádios de mudança de cor e de maturação, em videiras 'Cabernet Sauvignon', avaliadas por duas safras, com controle de invasoras por herbicida na linha de plantio (controle), ou consorciadas com plantas anuais, na sucessão moha-azevém (M-A) e trigo mourisco-aveia (T-A), ou com a perene festuca (Fest), manejadas com (ct) ou sem (st) a transferência dos resíduos culturais da linha à entrelinha. (Boeira & Daudt, 1995;Bell & Henschke, 2005). O manejo das plantas de cobertura pela roçagem e transferência do resíduo cultural da linha para a entrelinha das videiras não afetou a produção de uva, tampouco os teores de N amoniacal e os de N total na uva (Tabela 1).…”

“…Além disso, os produtos finais de metabolismo microbiano influenciam a composição do vinho (Bell & Henschke, 2005).…”

Are precision agriculture tools and methods relevant at the whole-vineyard scale?

“…In this particular area, the zones with higher NDVI, lower ECa and higher elevation had higher vigour, berry size and yield (Tables 2 and 3), as a consequence of a better water and nutritional status throughout the season as shown by the lower carbon isotope discriminating ratio and the higher nitrogen levels in berries. Water status has been already shown to be the most relevant factor determining vine yield and berry size in this region (Santesteban and Royo, 2006), and nitrogen is also known to significantly affect shoot and berry growth (Bell and Henschke, 2005). Carbon isotope discriminating ratio in berries has proved to be a very interesting tool to integrate plant water status during berry development and should be used in any research dealing with precision viticulture or modelling in areas where water limitations occur.…”