I’ve written a little bit about Harviestoun, and specifically their whisky cask aged Ola Dubh, before, but as head brewer Stuart Cail presented a session covering the beer in much more detail at The European Beer Bloggers Conference it seemed rude not to follow up my previous post with some information from the source. With cask ageing very much now in evidence across many of the young craft breweries, it’s interesting to see what a more traditional brewer has done with the idea, and the impact that they’ve had across the British brewing scene.
As with many things in the world of modern beer, the idea for ageing some of Harviestoun’s beers in wood came from the USA. In 2002 the company’s US agent asked if they could do some cask aged beer for him and, sourcing wood from Dalmore distillery, they did. Pleasingly, the first batch sold out and the importer returned asking for another, which gave them ideas.
First they shopped around for a producer to supply casks for the beer, as having a contract for supply is particularly important when the number of empty casks is becoming increasingly tight in the whisky industry. Highland Park where at the top of the list, having just been named distiller in the year and riding high on the resultant publicity – Harviestoun approached them and a deal was struck.
The rather impressively appointed room at the Ghillie Dhu
One of the initial worries from the Highland Park side was that the beer might be overpowered by the whisky heavy flavour compounds left in the wood of the cask, a fear that was laid to rest when it was decided to use Old Engine Oil as the base for the beer.
Named for both its resemblance to engine oil and distillery founder Ken Brooker’s former employ as an engineer at Ford, the Old Engine Oil is a thick and scarily dark beer. On the nose it’s meaty with huge amounts of very savoury, dark roasted barley, a light astringency and a bit of plasticine. To taste it starts out very bitter, with freshly crushed chocolate malt and a charcoal edge, although the body of the beer is relatively light and mild-like. It finishes with bitter grains and a hint of charcoal.
A first batch of casks were sourced from Highland Park, beer was filled into them and they were left for a few months to contemplate the universe. After it was deemed that they’d sat for long enough, they were decanted and bottled. Ola Dubh, gaelic for Black Oil, was born. The American importer took the lot.
With the first batch unavailable in the UK and the internet compressing the world of beer journalism, news of Ola Dubh’s existence started filtering into the UK. Further casks were already maturing and the staggered nature of batched maturation did wonders for promotion, with the first batches released in the UK snapped up eagerly when they were ready.
Under the Ola Dubh label they bottle a number of beers, all based on Old Engine Oil but differing in how long the cask was used to mature whisky before being repurposed to beer maturation – impressive as distillers aren’t well known for letting anyone know (often not even themselves) what was previously in a cask. Currently the ‘regular’ range consists of 12, 16 and 18 year old casks, with 30 and 40 year old ones, as well as a 1991 vintage, as limited editions.
Stuart (middle) and their US importer (right) with the first batch of Ola Dubh
The beer is filled into the wood with some residual yeast and a little bit secondary fermentation does happen in the barrel. They fill at about 11% and there is most likely some change in strength during maturation, however they dilute the beer back to 8% before bottling. The Old Engine Oil is known for being a bit lively during brewing and as such the casks do need to be vented from time to time, especially if they get hot – an occasional peril as they are often stored outside of the distillery. Fortunately they are in Scotland and use the side of the site that doesn’t get much sun (even for Scotland) for storage, but the casks are hosed down if they start getting warm to ensure they don’t get too hyperactive.
The beer stays in wood for between 4 and 6 months, depending on the casks and storage conditions. Generally the casks that have matured younger whisky take closer to 6, while those that have held whisky for longer are bottled closer to 4 months. This is a bit opposite to what you’d expect in the whisky world, with longer time in the cask extracting more flavour from the wood and leaving the barrel less suitable for reuse. However, the beer interacts with the wood quite differently, and I suspect that a lot of the flavour in the older cask editions is from compounds left behind in the wood by the whisky rather than the wood itself. Fortunately, while some of the casks wouldn’t be suitable for refilling with whisky, one property of Old Engine Oil saves the day – compared to whisky it’s like tar, helping to seal any leaks.
The Ola Dubh 12 year old is definitely a different beast to the Old Engine Oil that it comes from, with a very sweet nose backed up an umami rich soy sauce note. The sweetness comes from stewed raisins and berries, along with an astringent but sweet liquorice touch. To taste it’s again much lighter than the nose and colour suggest, with sweet fruit quickly swamped by dark roasted malt. Fortunately, stopping it from becoming unbalanced, the rich stewed fruit hangs around underneath. It finishes with char, Marmite and lots of bitterness initially, with some fruit creeping around the sides of the tongue as it lingers.
Similar to the Ola Dubh, the Old Engine Oil is also ‘liquored back’ before bottling, usually to 8%. However, the strong beer loving US market have their own special edition (now also available in limited quantities on the UK market) – Old Engine Oil Engineer’s Reserve – which Stewart brought a few bottles along to try. On the nose it was similar to the lower strength version, dominated by dark roasted malt, but also had a hint of bittersweet dark chocolate. To taste the theme continued with more fruity dark chocolate coming in along with the chocolate malt and charred woody notes. It finished with dark stewed fruit and even more heavily roasted malt.
The last of the Harviestoun beers I tried popped up during the final session of #EBBC13. A single cask release, using a sherry cask only once filled with whisky – a 40 year old Highland Park. It’s a very limited special edition being bottled in honour of the brewery’s 30th anniversary, and they brought along a few bottles for us to try at the conference.
On the nose it had the expected dark roasted malt, but sherry fruit popped out from behind it as the beer warmed – rich chocolate, a bit of cherry and some heavily sherried whisky. To taste it was heavy and rich, with low cocoa-solid chocolate, heavy sweet sherry, ruby port, cherry and a bit of an alcoholic punch – it was (noticeably) bottled at the cask strength of 11.3%. It finished with warming port and sherry notes, tempered by bitter coffee grounds.
It wasn’t the best weather for drinking heavy dark beers, being the hottest day of the year in Edinburgh, and I’m still not a fan of the Old Engine Oil, but I’ve got a spare bottle of the 30th anniversary beer on the shelf and it’s certainly one that I’ll revisit when it’s a little cooler.
Old Engine Oil
Porter, 6%. ~£1.25 per bottle from the Harviestoun webshop.
Ola Dubh 12
Whisky cask aged porter, 8%. ~£4 per bottle.
Old Engine Oil Engineer’s Reserve
Porter/Black Ale, 9%. ~£2.65 per bottle.
Ola Dubh Harviestoun 30th Anniversary
Whisky cask aged porter, 11.3%. Not yet available.