When most people think of the history of Irish whiskey and how it’s made, they think smooth, triple-distilled, easy drinking. But that’s only half the story. For centuries, Irish distillers were throwing oats, rye, wheat, and unmalted barley into the mash, creating spirits that were oily, spicy, and downright quirky.
- The Mash Bills That Time Forgot
- How Irish Whiskey Lost Its Soul
- The Revival: A Whiskey Time Machine
- Why This Matters for Whiskey Fans
- Final Sip
The problem? Those flavours were nearly wiped from history until whiskey historian (now) Dr. Fionnán O’Connor (author of A Glass Apart) dug into the archives as part of his PHD and uncovered dozens of forgotten mash bills. His research is now helping Irish distillers resurrect recipes that haven’t been tasted in over a century.
As I work my way through his published theses I wanted to write about the work he has down for Irish whiskey to date.
The Mash Bills That Time Forgot
Dr. Fionnán O’Connor has dug through forgotten ledgers and tax records to uncover dozens of old mash bills, these were the recipes distillers in Ireland used from as far back as 1324 to 1900s.
Unlike a lot of whiskey being made in Ireland today they it wasn’t just barley being used in the mash bill. They used:
- Oats which added creamy texture.
- Rye delivered peppery spice.
- Wheat brought softness.
- Unmalted barley gave weight and bite.
This cocktail of grains made Irish whiskey far more diverse than the “light and smooth” stereotype we know today.
Some brands are using these ingredients more like in the Redacted 002 Blackwater 5 Grain Double Pot Distilled Whiskey which include 5% rye, 15% oat, 10% wheat, 35% barley, 30% malted barley, and 5% Irish turfed malt, with all of the ingredients being Irish grown.
How Irish Whiskey Lost Its Soul
1. Taxes and Trade
British tax laws in the 18th and 19th centuries penalized malted barley, pushing distillers toward unmalted barley, oats, and rye. Ironically, these tax dodges created the unique Irish mash bills we now celebrate.
But by the early 20th century, new legal definitions of “Irish whiskey” narrowed the field. Add in trade wars after independence and U.S. Prohibition, and Irish whiskey was squeezed out of its biggest markets just as Scotch blends were booming.
2. Distillery Closures
At its peak, Ireland had 80+ distilleries. By the 1970s, just two survived: Bushmills and Midleton. Legendary sites like Powers’ John’s Lane and George Roe’s Thomas Street Distillery – once among the largest in the world – vanished, taking their house recipes with them.
3. Blends Take Over
When the Coffey still arrived in the 1830s, Scotch embraced it. Lighter, cheaper blends conquered the world. Irish distillers, stubbornly proud of pot still whiskey, were left behind. By the time they gave in, the unique mash bills were already history.
The result? Irish whiskey collapsed from world leader to near-extinction within a century.
The Revival: A Whiskey Time Machine
Here’s where it gets exciting. O’Connor isn’t just writing a dusty doctorate. He’s teamed up with Boann Distillery in Co. Meath to bring these ghost recipes back to life.
- Historic mash bills from the 1800s have been recreated.
- They’re aging in bourbon, rum, wine, and sherry casks.
- Early blind tastings? Shockingly complex. Creamy. Spicy. Totally unlike modern Irish whiskey.
It’s whiskey time travel, in a glass…
Boann Distillery even released a tasting pack with 10 single pot still samples from lost distillery mash bills named: The Vintage Mashbill Tasting Pack.
Why This Matters for Whiskey Fans
This project blows up the idea that Irish whiskey = light and smooth. Historically, it was:
- Spicier (rye-driven heat).
- Creamier (thanks to oats).
- Full-bodied and earthy (with unmalted barley).
And it raises a huge question: should Ireland (and the EU) update the legal definition of “Irish pot still whiskey” to reflect this history?
If so, we might see a whole new wave of bottles hitting shelves. Bottles that taste more like what our ancestors were drinking two centuries ago.
Final Sip
Irish whiskey is enjoying a renaissance, but this revival is different. It’s not about shiny new brands with trendy social accounts – it’s about resurrecting lost flavours that once defined the category.
So the next time you sip a pot still whiskey, remember: the smooth, friendly style we know today isn’t the full story. The ghosts of Ireland’s past are stirring again, and they might just be coming back to your glass sooner than you think.
A huge thanks to historian Fionnán O’Connor for unearthing this forgotten history and putting it back in the conversation and congratulations on his PhD success. His full research can be read here: Still With Us essential (but very long 300+ pages) reading for anyone serious about whiskey.
To follow along with the journey and revival that Fionnán is leading, head over to Creatur.ie and make sure to sign up for ongoing learning and updates.