Prediction of potassium bitartrate saturation temperature in wines

Result code in IS VaVaI

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Result on the web

<a href="https://www.melpro.cz/" target="_blank" >https://www.melpro.cz/</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Prediction of potassium bitartrate saturation temperature in wines

Original language description

Electrodialysis (ED) is one of the techniques used for the tartrate stabilisation of wines. The problem of ED in such an application is that it is not selective for potassium (K+) and bitartrate (HT-) ions, but it also removes other cations (Ca2+), anions (sulfates, phosphates) and organic acids (citric, malic, lactic, succinic, acetic acid etc.). In order to achieve a desired tartrate stability of wine expressed by means of potassium bitartrate (KHT) saturation temperature (Tsat) it is necessary to demineralise wine more than would correspond to the portion of KHT removed by conventional techniques such as cold stabilisation of wine. In order to obtain an absolutely stable wine (it corresponds to a Tsat in the range of 0 to -4 °C) using RALEX® heterogeneous ion-exchange membranes available from MEGA a.s. (Czech Republic), conductivity of wine must be reduced by approximately 40 to 60 %, although a Tsat in the range of 5 to 15 °C is often sufficient due to a slow kinetics of KHT precipitation. Undesirable changes of organoleptic properties occur simultaneously with the demineralisation of wine by ED, however. Therefore, ED is suitable for certain sorts of wine only. The course of demineralisation of wine by ED (concentration profiles of components for the respective levels of demineralisation) can be modelled provided that the initial composition of wine is known. Permeabilities for the respective ions needed can be evaluated from experimental data1 and used in combination with dissociation equilibria for present organic acids for these purposes. The dependence of KHT solubility in the system of water – ethanol on ethanol content and temperature can be found in literature2. The dependence of the equilibrium constant (solubility product for KHT) on temperature is expressed by the Van’t Hoff equation. In this work, the unknown constants in the equation were determined from experimental data (pH, concentrations of K+ and tartaric acid, Tsat) for four sorts of wine (two red wines: Modrý Portugal, Cabernet Moravia; two white wines: Veltlín zelený, Rulandské šedé) and six levels of demineralisation (0, 10, 20, 30, 40 and 50 %) using the nonlinear regression. A good correlation between composition of wine and calculated Tsat has been found. The presented method can be used to find those sorts of wine, which are suitable for the treatment by ED based on their initial composition. ED should be capable of significantly reducing Tsat at a low demineralisation level for such sorts of wine.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20402 - Chemical process engineering

Project

<a href="/en/project/LO1418" target="_blank" >LO1418: Progressive development of the Membrane Innovation Centre</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů