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In this episode of The Wine Lab, Andreea takes you inside one of winemaking’s most iconic tools — the oak barrel. From Celtic craftsmanship to modern coopering, we’ll explore how fire, oxygen, and time turn simple wood into a vessel of transformation.

Discover why oak became the gold standard, what happens during toasting, and how micro-oxygenation softens tannins and stabilizes color. Learn about the differences between French, American, and Hungarian oak, the chemistry behind aging, and even the future of sustainable cooperage — including experimental ideas like biochar barrels and hybrid woods.

It’s the story of the barrel as both instrument and ingredient — a breathing partner that connects forest, fire, and fermentation in one seamless conversation.

Glossary of Key Terms

Barrique – The standard Bordeaux-style oak barrel, holding about 225 liters of wine. Its small size increases oak influence and oxygen exposure.

Toasting – The process of heating the inside of a barrel with fire to bend the staves and develop flavor compounds like vanillin, furfural, and spice phenols.

Ellagitannins – Polyphenolic compounds in oak wood that stabilize color and influence mouthfeel during aging; they also act as antioxidants.

Micro-oxygenation – The slow diffusion of oxygen through the wood, which polymerizes tannins, softens structure, and develops complexity in wine.

Foudres – Very large wooden vats (1,000–20,000 L) used for aging; they allow oxidative benefits of wood with minimal oak flavor influence.

Hemicellulose and Lignin – Structural components of wood that decompose under heat to form aromatic compounds like vanilla, caramel, and smoke notes.

Angel’s Share – The portion of wine (water and alcohol) that evaporates through the barrel over time, concentrating flavor and altering balance.

Acetaldehyde – A compound formed by mild oxidation of ethanol; in small amounts, it adds brightness and nuttiness, but in excess it can smell bruised or sherried.

Biochar – A carbon-rich material produced by pyrolysis of biomass in low oxygen; being explored in cooperage as a sustainable, oxygen-modulating material.

Hybrid Barrel – A barrel made from different woods (e.g., oak staves with acacia or cherry heads) to achieve specific flavor or structural goals.

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For more detailed wine science checkout my YouTube channel here: https://www.youtube.com/@Enology_channel

Send me your thoughts at ibotezatu5@gmail.com

In this episode of The Wine Lab, we explore the science and story of tannins: what they are, where they come from, and why some wines feel silky while others grip your gums.

From the ancient craft of leather tanning to modern barrel aging, we trace how these polyphenolic compounds shape wine’s structure, color, and longevity. We’ll look at how fermentation temperature, pH, and rising alcohol shift what gets extracted from skins and seeds — and how acidity changes the way tannins feel on your palate.

You’ll also learn why black tea gives you the same dry feeling as a young Cabernet, that tannins aren’t probably the cause of wine headaches, and why some white wines have more tannin character than you might think.

So pour a glass, and let’s explore the chemistry of feeling wine.

Astringency – The tactile, drying sensation in the mouth caused by tannins binding to salivary proteins, reducing lubrication. It’s a feeling, not a flavor.

Tannins – Polyphenolic compounds found in grape skins, seeds, stems, and oak. They contribute structure, color stability, and aging potential to wine.

Condensed tannins (Proanthocyanidins) – Tannins naturally present in grapes; built from flavan-3-ols. They shape a wine’s body and mouthfeel.

Hydrolyzable tannins – Tannins derived from oak barrels, composed of gallic or ellagic acid units. They provide antioxidant capacity and subtle structure during aging.

Anthocyanins – Water-soluble pigments in grape skins that give red and purple wines their color. They stabilize when bonded to tannins.

Maceration – The period during fermentation when grape skins and seeds are in contact with the juice, allowing extraction of color, flavor, and tannins.

pH / Acidity – A measure of wine’s acid level. Lower pH (higher acidity) makes tannins feel firmer; higher pH makes them feel softer.

Polymerization – The process where small tannin molecules link into longer chains over time, softening texture and reducing astringency.

Ethanol – The alcohol formed during fermentation. It changes the solubility of phenolics, enhancing seed-tannin extraction but slowing pigment release.

Tribology – The study of friction and lubrication. Used in wine sensory research to explain how tannins affect mouthfeel.

Ellagitannins – Oak-derived tannins that help stabilize color and protect wine from oxidation during barrel aging.

Extended maceration – A winemaking technique where wine remains on skins after fermentation to extract additional tannins and complexity.

Aging – The slow chemical evolution of wine after fermentation. Tannins polymerize and precipitate, softening texture over time.

Bitterness – A taste detected by receptors on the tongue, distinct from astringency (a physical sensation).

Color stability – The persistence of wine color over time, maintained by reactions between tannins and anthocyanins that form more stable pigments.

Support the show

For more detailed wine science checkout my YouTube channel here: https://www.youtube.com/@Enology_channel

Send me your thoughts at ibotezatu5@gmail.com

What do Port, Sherry, Madeira, Marsala, and Vermouth all have in common? They’re wines with an extra ingredient — spirit. In this episode of The Wine Lab, Dr. Andreea Botezatu explores how fortification began as a practical solution for preserving wine on long sea voyages and evolved into a craft that shaped trade, taste, and culture.

From Shakespeare’s Falstaff praising “sack” to George Washington’s love for Madeira, we’ll travel through history and a little chemistry to understand what makes fortified wines so enduring. You’ll learn about their different origins, what spirits are used (always grape-derived!), how to serve them, and the best ways to enjoy them — from chilled Fino with tapas to Vintage Port and Stilton by the fire.

A story of science, adaptation, and taste — all in one small pour.

Glossary

Aguardente vínica

A neutral grape brandy used to fortify Port and other Portuguese wines. It typically sits around 77% ABV and is added mid-fermentation to stop the process and preserve natural sweetness.
🔗 Instituto dos Vinhos do Douro e do Porto (IVDP)

Amontillado

A style of Sherry that starts aging biologically under flor (like a Fino), then continues oxidatively after the flor dies off, creating nutty, caramelized aromas.
🔗 Sherry Wines – Amontillado Overview (Consejo Regulador)

Copita

A small, tulip-shaped glass traditionally used for serving Sherry. Today, the Sherry Council recommends small white-wine glasses instead, to allow greater aromatic expression.
🔗 Sherry Wines – How to Serve Sherry

Flor

A layer of yeast that forms naturally on the surface of Fino and Manzanilla Sherries, protecting the wine from oxidation and producing unique acetaldehyde-driven aromas (almond, green apple, saline).
🔗 Sherry Wines – The Role of Flor

Fino

The driest style of Sherry, aged entirely under flor. Fresh, crisp, and delicate, often served chilled with tapas or fried foods.
🔗 Sherry Wines – Fino

Madeira

A fortified wine from the Portuguese island of Madeira, famous for its oxidative and heat-influenced production process (estufagem). Styles range from dry (Sercial) to rich (Malmsey).
🔗 Instituto do Vinho, do Bordado e do Artesanato da Madeira (IVBAM)

Marsala

A fortified wine produced around the city of Marsala in western Sicily, Italy. Often made with local varieties like Grillo and Catarratto, and sometimes enriched with cooked grape must (mosto cotto).
🔗 Consorzio di Tutela del Vino Marsala DOC

Oloroso

A Sherry style aged entirely by oxidation, resulting in a full-bodied, nutty, and often semi-sweet wine.
🔗 Sherry Wines – Oloroso

Port

A fortified wine from Portugal’s Douro Valley, produced in various styles (Ruby, Tawny, Vintage). Fermentation is stopped early by adding grape spirit, retaining residual sugar.

Support the show

For more detailed wine science checkout my YouTube channel here: https://www.youtube.com/@Enology_channel