Ep 237 – The Science of Smell: Understanding Wine Aromas with Sietze Wijma

In this sensory-driven episode, Janina is joined by Sietze Wijma, founder of The Art of Tasting, to explore how flavour molecules shape our experience of wine. From chemistry to culture, Sietze shares how our environment, memories, and even our saliva can change what we taste in the glass. Together, they unpack the science behind wine aromas, tasting faults, and why perception is as much about learning as it is about the senses.   Shownotes [00:26] Janina introduces her guest, Sietze Wijma, recognised at the 67 Pall Mall Global Communicator Awards for his work blending sensory science and wine education. [01:49] Quick wine fact — how saliva enzymes alter sweetness and release fruity aromas in Sauvignon Blanc. Based on info from The Cynic’s Guide to Wine by Sunny Hodge (Guest on Ep 232) [03:41] Sietze explains The Art of Tasting and how adding isolated flavour compounds helps students identify key aromas. [04:31] How flavour molecules like those in green bell peppers naturally occur in wine. [05:28] Using “spiked” neutral wines as a training tool before tasting commercial wines. [06:19] Butter, vanilla, and yogurt notes — breaking down malolactic fermentation, oak ageing, and lees stirring. [08:00] How culture shapes perception: diacetyl (buttery aroma) described as baklava in Turkey or dahi in India. [09:36] Sietze’s journey from studying flavour chemistry in beer to founding his own wine-focused aroma lab in the UK. [11:03] The “bird-watching” analogy — tasting is about recognition, not sensitivity; anyone can train their palate. [12:57] Identifying key wine aroma families — pyrazines, TDN, and rotundone — and how they appear in specific grape varieties. [13:55] Pyrazines and their link to green bell pepper notes in Sauvignon Blanc, Cabernet Franc, and Carménère. [15:10] TDN and the petrol character in Riesling — how sunlight and bottle age intensify the aroma. [17:04] Rotundone and the black-pepper signature of cool-climate Syrah and white-pepper notes of Grüner Veltliner. [20:04] How different cultures interpret the same aroma — ginseng and pyrazines in Chinese Cabernet Sauvignon. [21:27] The “ladybug taint” — an uncommon wine fault caused by crushed beetles releasing pyrazine compounds. [23:32] Common wine faults explained: cork taint (TCA), reduction, light strike, oxidation, and brettanomyces. [28:09] Story time — Sietze recalls mistaking oxidation for an open-too-long bottle in Austria. [30:14] Brettanomyces and the fine line between savoury complexity and spoilage. [32:31] The Château de Beaucastel example — when Brett becomes part of terroir and debate. [33:13] Tasting myths: why aromas like “green bell pepper” don’t mean actual allergens in wine. [34:37] How to improve blind tasting skills at home using aroma kits and DIY spiked wines. [36:28] Why tasting side-by-side is key to better identification and learning. [37:55] The “mouseiness” fault — why some aromas appear only after tasting due to pH and acidity. [42:46] Helen Keller’s quote on scent and memory — a poetic close to a science-rich episode. 📩 Questions or feedback? Email: [email protected] 📸 Instagram: @eatsleep_winerepeat 🎥 YouTube: Eat Sleep Wine Repeat 🌐 Website: www.eatsleepwinerepeat.co.uk Until next week – cheers to you! 🥂 THE EAT SLEEP WINE REPEAT PODCAST Featured in Decanter Magazine and Radio Times, and ranked among the Top UK Wine Podcasts by Feedspot. RECOGNITION: – Finalist, 67 Pall Mall Award for Best Global Wine Communicator in Audio (2025) – Shortlisted, IWSC Emerging Talent in Wine Communication (2025) – Ranked #18 in 2024 and #22 in 2025 on Drinks Retailing’s Most Influential People in Drinks list