Right then, readers: sit down and strap yourselves in for a spot of beery education…
International Bitterness Units – or IBUs as they are more commonly abbreviated – are something that really only brewers and beer geeks talk about. IBUs are a measure of bitterness in beer, with one milligram of isomerised alpha acid (the main bittering acid derived from hops) equal to one IBU. It’s important, however, to note that a beer’s perceived bitterness often will not match up with its IBU count. For instance, an Imperial Stout with 60 IBUs will usually taste less bitter than a German Pilsner with 40 IBUs due to its higher level of sweetness and body from its heftier malt bill.
With us so far? OK, let’s continue…
It’s generally accepted that the palate reaches its bitterness threshold at about 100 IBUs. So when Swan Valley’s Mash Brewing decided to commemorate its 500th batch by brewing an Imperial IPA with a calculated 500 IBUs, I knew to expect a ludicrously bitter, hoppy beer. More than a year after it was brewed, it remains (to the best of my knowledge) the most highly bittered beer brewed in Australia.
Brewed in August 2011, Mash 500 was the last beer at Mash brewed by the brewery’s foundation brewer, Dan Turley.
"This was a really special brew," says Dan (pictured on brew day above). "We wanted to do something a little different for our 500th brew and after many beers and much discussion, we decided it couldn’t be anything else other than a beer with 500 IBUs. Crazy, perhaps undrinkable, but who cares, it sounded like fun!"
The hops chosen were all high alpha acid varieties in an effort to hit the targeted 500 IBU mark, although this still resulted in close to 30kg of hops in the kettle – several times more than the amount used in Mash’s regular beers. Summit, Millennium, Magnum and Galena hops were utilised in the boil, with Cascade and Citra used for dry hopping.
The malt bill was comparatively simple, with Munich and Crystal malts lending toasty, biscuity and caramel notes to the beer, while a "fair whack" of sugar was used to give the product a dry finish and help get the alcohol up to a considerable 8.2 percent ABV.
"The brew day itself was great fun," says Dan. "A full mash tun and an absolute truck load of hops. These are the sort of brew days that brewers live for and Jack (Mash’s assistant brewer, Jackson Purser) and I were loving it. Unfortunately the cleanup was a real bastard – the sheer amount of hops blocked everything in sight – the kettle outlet, the heat exchanger, the drains – the brewhouse looked like a hop sludge bomb had exploded! It took a day or so to clean up everything, but at least the brew was happily in the fermenter!"
On inspection in the bright beer tank, the beer appeared clear and was packaged in 500mL bottles. After a few weeks, when the first bottle of Mash 500 was opened, the beer had a lot of loose sediment and a huge amount of aggressive, raw bitterness. It was decided to cold store the rest of the 500, giving it time to drop clear and hopefully mellow its bitterness to a more drinkable level.
More than a year later, the 500 is finally on sale at all three Mash venues. Priced at $15 for a 500ml bottle it isn’t exactly cheap, but entirely worth it for the dedicated hop head. Some hop matter remains in the last three centimetres of the bottle, but not to worry – Mash’s bar staff have been trained to pour the beer with a steady hand, leaving all sediment behind.
Poured into a tall, tapered "regular" glass, the 500 is deep amber-orange in colour and when held to direct light, you can tell that the year in cold storage has done its job – the beer is crystal clear. A dense foam head the colour of clotted cream sits atop and stays put right down to the bottom of the glass.
The aroma is surprisingly balanced, with malty scents of baking biscuits and burnt toffee complimenting the piny, citrusy American hops. On the front of the palate is big sweetness and malt-derived flavours of biscuit and caramel, which are promptly overrun by an avalanche of hop flavour and huge bitterness reminiscent of biting into the white pith of an orange.
The body is medium-full with moderate carbonation and fine bead, resulting in a smooth, almost creamy mouthfeel. Warming alcohol lingers in the dry finish, reminding you that this is a strong beer not to be taken lightly.
So if you’re a dedicated hop head, what else needs to be said? Head to your nearest Mash venue and try this monster brew before it runs out!
Special mention goes to the suppliers – Sandy Ross (hops), David Cryer (malt) and Dr Wayne Reeve (yeast) – who together donated all of the ingredients for the monster brew.
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