## 2 Volatile Wood Composition
### _Q. pyrenaica_ Wild
In seasoned cherry wood, the three most abundant compounds were 3,4,5-trimethoxyphenol, methyl syringae, and benzoic acid and in toasted wood they are syringaldehyde and sinpaldehyde. Cherry wood after seasoning and toasting was the poorest in vanillin, followed by acacia, with almost less than half the concentration of _Quercus_ wood. However, especially after medium toasting the syringaldehyde content of cherry wood was higher than that of traditional woods 455-535 \(\upmu\)g/g compared to 221-226 \(\upmu\)g/g, so the phenolic aldehydes/phenyl ketones content was high (Figure 1d). The furfural content in seasoned wood was very low and the increase during toasting was very small compared to that of the other woods, which makes toasted cherry wood very poor in this compound, and generally in furanic compounds (Figure 1b-d). In general, the volatile phenols presented in Tables 3 and 4 show a behaviour during toasting similar to _Quercus_, presenting contents similar to traditional woods, although the wood after medium toasting presents lower contents of guaiacol, 4-MG and syringol. Faxinus excelsior (European ash) and Fraxinus americana (American ash)  
Ash wood did not show any unique volatile compounds, as all compounds present in ash wood were detected in at least one other wood, be it acacia, chestnut, cherry or _Quercus_. However, quantitative differences can clearly be used to identify toastedash wood, with tyros being the most interesting, since, although in seasoned wood it is found in this wood and in oak wood, after toasting it was only found in ash wood and in high concentrations, 24.6 and 26.4 \(\mathrm{\SIUnitSymbolMicro g}\) in the European and American species, respectively. Furthermore, this wood is quantitatively different and with higher contents in certain volatile compounds than all the woods compared (acacia, cherry, acacia, _Q. pyrenaica_, _Q. petraea_ and _Q. alba_), especially after toasting, including: catechol, 3-methylcatechol, homovanillyl alcohol, coniferaldehyde, 2-phenoxyethanol, 1-hydroxy-2-butanone, 1-acetyloxy-2-butanone, \(\gamma\)-butylrolactone, solerone, 3,5-dimethylcyclotene, 4,5-dimethyl-2-cyclohexen-1-one, 2-furanmethanol, 3-ethylcyclotene, \(\alpha\)-methylcrotonolactone, solerone and 3-hydroxybenzaldehyde. Focusing on volatile compounds sought after by consumers, it was observed that ash wood also had high contents of guaiicol, isoeigenpol, syringol and maltol, as well as vanillin, syringaldehyde and acetovanillone, when subjected to medium toasting (Table 4). Therefore, after light and medium toasting it is a wood with more volatile phenols (Figure 1c,d) and after medium toasting more phenolic aldehydes/phenyl ketones than _Quercus_ (Figure 1d). However, the wood is rather low in furfural (Table 4) with very low contents of furanic compounds after all cooperage treatments (Figure 1b-d). There are compounds that are not detected in ash wood but are in traditional woods, such as _trans_ and _cis_ lactones, which are of great interest. American toasted ash wood appears to be more aromatic than European ash wood in most of the compounds [23; 65], as well as in the compounds represented in Table 4.  
_Morus alba_ (mulberry)  
The volatile composition of this wood has been little studied, and no studies were found that focused on its toasting, a very important process in the formation of aromas. After seasoning, mulberry wood seemed to be the poorest in volatile benzene compounds, and certain compounds of great aromatic interest, such as eugenol, methoxyeugenol, vinylguiaicol and syringol, were not detected [71]. The concentrations of vanillin and syringaldehyde found were very low; however, it presented important extraction percentages, especially of vanillin, which differed considerably from those of oak wood, probably due to the different porosity of the wood [71].