###### Abstract
The range for cork taint (impact substance: TCA) [20] is 1.4 to 210.0 ng TCA/L [21; 22; 23; 24], and for animal phenolic aroma (impact substance: 4-ethylphenol (4-EP), 4-ethylgaiaicol (4-EG), 4-ethylcatech (4-EC)) [25; 26] is 50-968 \(\mu\)g 4-EP/ L [27; 28; 29; 30; 31; 32], 33-135 \(\mu\)g 4-EC/L [27; 28; 29; 30; 31; 32], or 0.9 to 33 \(\mu\)g 4-EG/L [33; 34; 32]. A more detailed definition of the threshold value or the method used for determination is usually not specified. A very important factor is the medium in which the substance is present, and in most cases, not all the data have been made available either. The problem with threshold values is that new techniques should not be finally assessed purely analytically but must include a sensory study. For this reason, the results of [8; 15] should be verified since no sensory analysis was conducted in either study. Besides the effectiveness in terms of minimising wine defects, it is, of course, necessary to assess the effect of these filter layers on the overall quality of the products after filtration, especially with regard to the volatile profiles of the wines and overall sensory perception. Already [11] compared wines filtered with layers with the unfiltered wine regarding some main aroma compounds, mainly higher alcohols, carboxylic acids, carbonyl compounds, and a few ester compounds, and carried out sensory tests. It was found that the wines filtered with Fibrafix(r) TX-R layers were sensory but also analytically only marginally distinguishable from the noncontaminated wines and that the lead substance of the cork flavour, 2,4,6-trichloroanisole, was sufficiently reduced. However, additional studies should be carried out because specific aroma groups, especially free monoterpenes, wood aroma substances, and a wide range of ester compounds, can significantly influence the aroma of the wines. From the results of [11], it can also be deduced that the four ester compounds investigated were reduced much more than the analysed higher alcohols, so a detailed look at ester compounds would make the most sense because it can be assumed that there is a stronger aroma loss. Little is known about the aroma loss in conventional depth filtration with sterilisation filter layers, so the comparison of Fibrafix(r) TX-R sheets with conventional depth filter layers would make sense throughout. While Fibrafix(r) TX-R sheets are made of purified and bleached cellulose with the natural inorganic filter aids zeolite and polyamidoamine (<3%), the conventional depth filter layers for sterilisation are made of purified and bleached cellulose with natural inorganic filter aids diatomaceous earth (DE, Kieselguhr) and perlite. Significant differences in aroma loss and reduction in bad taste aromas are to be expected already because of the different compositions of the used filter layers. The aim of this study was to test the filter sheets of Filtrox (FIBRAFIX(r) TX-R, Zwingen, Switzerland) for the reduction in mould aroma (geosmin) and cork taint (TCA) and, for the first time, for the reduction in the impact compounds of \"animal\" phenolic aroma (4-EP, 4-EG, 4-EC). Additionally, we planned to obtain an overview of the decrease in important volatile compounds such as a number of major and minor esters, free monoterenes, and wood aroma compounds. A comparison with conventional depth filter sheets was also included in the study. These tests were aimed not only at laboratory scale but also at practice-relevant experimental designs, and not only analytical but also sensory tests were carried out. Filtrox also provided a newly developed filter sheet for the special reduction in \"animal\" phenolic aroma for testing. These additional layers have been examined in a practice-relevant experiment for their reduction power in relation to the leading substances of \"animal\" phenolic aroma, and the results have been put into context with the results of filtration with the patented Fibrafix-TX-R layers.