Charles Denby is the co-founder and CEO of Berkeley Yeast, a company that’s reimagining fermentation through genetics. With a PhD in molecular and cell biology from UC Berkeley, Charles and his team are using genetic science not to replace brewing tradition, but to enhance it — designing new yeast strains that can transform how beer, wine, and even spirits are made.In this conversation, we dive deep into the biology that underpins flavour. We unpack what yeast actually is, why it produces alcohol, and how its metabolism creates the esters and aromatics we love in drinks. Charles explains how fermentation conditions shape flavour, how lager and ale yeasts differ, and what really happens inside the tank at every stage of fermentation.From there, we go microscopic — exploring yeast genetics, DNA modification, and the molecular tools that make it all possible. Charles shares how Berkeley Yeast engineers strains to enhance tropical aromas in hazy IPAs, introduce new layers of bitterness, or even make brewing non-alcoholic and healthier beers more efficient.We also discuss the broader implications of this technology — from applications in wine and spirits to the stigma surrounding GMOs and what “responsible innovation” really means in the drinks world.

This is a fascinating deep dive into the invisible world that drives fermentation — and how science is quietly shaping the future of flavour.If you like this content please consider subscribing.

00:00 Introduction

02:34 Charles’ Background in Science & Origins of Berkeley Yeast
10:29 What is Yeast? Why Does it Produce Alcohol? Yeast Metabolism
16:49 Fermentation Conditions, Ester Metabolism
22:04 Yeast Species: Lager & Ale Yeasts
24:24 Stages of Fermentation
28:34 Nutrients for Fermentation, Amino Acid Synthesis, Diacetyl Production
36:34 Why Is Beer Fizzy? Production of CO2 During Fermentation
37:34 Yeast Genetics, Cell Biology, Evolutionary Biology
42:29 Modifying Yeast DNA, Molecular Scissors, Polymerase Chain Reaction
55:54 The Complex Web of Genetic Modification
1:01:14 Testing Yeast in Berkeley Yeast’s Microbrewery
1:04:04 Comparing Hazy IPA Yeasts, Creating Tropical Aromas
1:09:19 Engineering Yeast for Bitterness
1:12:04 Brewing Non-Alcohol Beer, Vacuum Distillation: Method, Downsides
1:16:54 Brewing Beer for Health
1:22:17 Applications in Wine: Flavour, Low-Alcohol, Cultural Knock on Effect
1:26:14 Residual Sugar in No/Low Alcohol Ferments
1:27:59 Applications in Spirits: Flavour & Efficiency
1:30:49 The Berkeley Yeast Business Model, Lifespan of Yeast Cultures, Competition
1:35:44 Overcoming the Stigma of GMO, Responsible Technology, Defining GMO in Beer