Saturday, 3 September 2011

Thornbridge Oatmeal Stout

To celebrate their forthcoming Great British Homebrew Challenge the good people at Thornbridge have come up with a new recipe for an oatmeal stout to get everyone's imagination kickstarted.

Thornbridge are well known for their innovation in brewing, and it's brought them award after award in the industry, and well deserved those awards are too.  And their slightly radical thinking extends to this stout recipe which is, at first glace, unusual.

The grist is pretty straightforward - mostly pale barley with roasted barley and oats.  But the hops, while being of  traditional varieties, are certainly not a traditional usage.  A stout is usually hopped for a well-balanced bitterness, and most of the flavour comes from the malts.  What is not so usual is a huge amount of post-boil aroma hops - 300g in a 25 litre batch.

It's fair to say that it's not been widely accepted as a good idea on some of the homebrew forums I read, but it is very clear that Thornbridge know their business a lot better than I do, so I've given it a go.


4590g Maris Otter Pale Malt
273g Chocolate Malt
273g Malted Oats
219g Crystal Malt
109g Roasted Barley

Mash in 14.7 litres at 66C, sparge with 20 litres between 70C and 77C

Boil schedule - 75 minute boil:
45g East Kent Goldings [5.6%] - 75 mins
1 tsp Irish Moss - 10 mins

After boil:

150g East Kent Goldings [5.6%] - 60 minute aroma steep
100g Fuggles [3.8%] - 60 minute aroma steep
50g Fuggles [4.9%] - 60 minute aroma steep

I ended up with 23 litres into the fermenter with an OG of 1.060.  That's much higher that the 1.053 that BeerSmith tells me I should expect, with an efficiency of 75%.  I think that my BIAB mash/sparge method is a bit more efficient than that though - perhaps closer to 80%+.

The two different types of Fuggles, with different Alpha Acid measurements were from different suppliers - the 50g being the end of a previously opened packet.

The yeast I pitched was Wyeast 1084 Irish Ale, harvested from the fermentation from this year's Xmas Ale, made up into a starter a few days before brew-day.

However, fermentation didn't go strictly as planned.  The gravity dropped from 1.060 to 1.020 over 14 days, but there it got stuck. Even rousing the yeast didn't help.  I was worried that I'd under-pitched the yeast, so added a fresh packet of Wyeast 1084 (I had an extra pack due to a supplier mix-up), but even that didn't budge the gravity.

After a week at 1.020 I admitted defeat and kegged it (and filled 8 bottles too).

I'm not sure why it's got such a high SG.  Perhaps I misread the mash temperature, or measured a cool-spot in the mash, and actually mashed at a higher temperature than I wanted, and thereby extracted many more unfermentable sugars than I intended?  Don't know.

Still, with an OG of 1.060 and an SG of 1.020 that's a 5.2% Abv beer.

I'll update this post with proper tasting notes once it has conditioned and I've had a sip.  However, initial tastes of the gravity samples I've taken have been, OK, but not great.  Surprisingly all those late hops aren't really that prominent in either the flavour or the nose - but the roasted barley is.  Once that has mellowed out a bit (which it will with conditioning) it might leave more room for the hops.

A grower, not a show-er, this one.



  1. Cant wait to hear how this one turns out. Mental amount of hops for a stout

  2. Might be the oatmeal. I did a RIS with oatmeal and that finished high, then again RIS's do. Had one last night, 1.026 FG!