## 3 Results and Discussion
### Volatile Profile Analysis  
In this section, the distribution of the volatile profiles was studied to determine the effect of terroric factors such as season (year), geography (location), and wheat variety. In total, 51 volatile compounds were identified in the twenty newly made spirit samples (Tables 10 and 11). The aroma profile consisted of acetals (2), alcohols (12), aldehydes (9), benzenes (2), esters (19), ethers (1), furan (1), ketones (3), lactone (1), phenol (1). The volatile compounds in Tables 10 and 11 in Appendix 0.A offer a detailed volatile structure of the new-made samples, which were used for multivariate analysis. Ethanol, ethyl acetate, phenylethyl alcohol, 3-methyl-1-butanol, and 2-methyl-1-butanol were identified as the most abundant volatiles across the samples. Ethanol is the main alcohol in all distillates, so it was expected to be a dominant compound (the abundance of ethanol is not a reflection of the true ethanol content as the sample was introduced as a 1:20 split onto the GCMS so as not to saturate the column and detector with ethanol to prevent ethanol overlapping with other early eluting volatile components). Ethyl acetate, with its sweet and fruity attributes, was prominent, adding to the complex sensory profile of the whiskey. The concentration of ethyl acetate is indicative of a balance between yeast metabolism and the conditions during fermentation and distillation [25]. Phenylethyl alcohol, known for its rose-like honeyed odour profile, was also detected in significant quantities. This aromatic alcohol is associated with higher perceived aromatic complexity and quality in distilled spirits [26]. The higher alcohols, or fused alcohols, such as 3-methyl-1-butanol and 2-methyl-1-butanol, are important components due to their impact on the overall character of the spirit. These compounds are often linked to malty and roasted sensory notes, contributing to the complexity of the aroma. Their concentration can serve as an indicator of yeast metabolism during fermentation, as well as the quality and characteristics of the raw material employed [27]. Principal Component Analysis  
The analysis helped in examining clusters formed by whiskey in regards to the distribution of volatile compounds based on the location, year, and variety, as shown in Figure 1.  
Figure 1: PCA Bi plot of separation based on the volatile profile (samples + volatiles); sample IDs present in Table 10.  
Figure 1 presents a PCA plot, where each point represents an individual whiskey sample plotted against the first two principal components (PC1 and PC2), which together capture 43.3% of the total variance in the volatile compound data. The samples are distributed across all four quadrants, indicating a wide range of volatile compositions. However, the lack of distinct clustering suggests that some samples share more similarities than differences in their volatile profiles. Volatiles distribution (a) Aldehyde and Ester  
Elation and Viscount from the location Carlow and Torp from Tipperary, from the year 2020, had a higher concentration of aldehydes (straight chain, branched chain, and aromatic) and esters. These compounds are known to contribute to the fruity, floral, and sometimes nutty flavour of whiskey. In comparison, a group of samples from 2021-LG Astronomer, Torp, Viscount from Carlow, LG Astronomer, and Torp from Tipperary had a higher abundance of mainly aldehydes and a very low abundance of esters. Elation Tipperary 2021, Viscount Tipperary 2021, Revelation Carlow 2021, and LG Astronomer Carlow 2020, Revelation Carlow 2020, and Revision Tipperary 2020, located on the negative side of the PC-1 plot were characterised by a low abundance of aldehydes and have a high abundance of specific esters.