Source: https://www.linkedin.com/in/john-angus?miniProfileUrn=urn%3Ali%3Afsd_profile%3AACoAACDoloEBC9FraHvbRJap2P6xtCR8YHrTci0&lipi=urn%3Ali%3Apage%3Ad_flagship3_detail_base%3BYm78cMbgTsSZ8n9vAhb%2F%2BQ%3D%3D

💡 Think whisky’s flavour starts in the cask? It actually begins with the barley — and the chemistry of malting sets the whole thing in motion.

As a chemist wanting to transition into distilling, I’ve been diving into how malted barley unlocks the sugars, amino acids, and flavour compounds that shape every whisky’s identity — long before fermentation or aging begins.

🌾 Starch to Maltose – During germination, enzymes like amylase break down starch into maltose. Yeast uses this sugar to produce ethanol and fruity esters during fermentation.

🧪 Protein to Amino Acids – Proteases free up amino acids, which are essential not only for yeast health but also for Maillard reactions and ester formation.

🔥 Kilning & Toasting – Heating the malt changes its flavour profile:
• Low Toast – Enzymes remain active, preserving grassy, grainy notes.
• Medium Toast – Maillard reactions begin, forming maltol and toasty cereal flavours.
• Heavy Toast – Higher heat forms furfural and 5-HMF, bringing caramel, biscuit, and dark fruit notes.

💬 Have you noticed how malt style affects your favourite whisky? Do you lean toward the lighter, grassy grain base — or those richer, roasted malt notes? Drop your pick below!

📌 Infographic attached — check it out!