Old Rasputin vs. the XV... a question of IBUs

So i had my first Old Rasputin Anniversary XV this past weekend and loved it. I'm thinking about replicating it at home and have seen several Old Rasputin clones, but none specifically mimicking the Old Rasputin XV Anniversary.

The easiest solution would seem to be to brew up an OR clone, and add bourbon-soaked oak chips to achieve the OR XV flavour profile BUT i have noticed one glaring difference between the two: the Classic, regular Old Rasputin has an IBU of 75... whereas the Old Rasputin XV Anniversary brew (the one i'm interesting in duplicating) has an IBU of 38. The XV is also at 11.9% while the classic is at 9%... but that could be addressed through the addition of bourbony-oak.

http://www.northcoastbrewing.com/beer-rasputin.htm
http://www.northcoastbrewing.com/beer-rasputin-barrel-aged.htm

This makes me think there'd be more to duplicating the XV brew then just adding bourboned oak to a classic OR clone...

As i understand it, IBUs are based on perceived bitterness. The bourbon & oak *could* be reducing the perceived hop character resulting in a lower IBU, while the actual recipe of the beer (and more notably, the hop schedule) is identical??? Or it could be a case of less hops added to the XV.

Anybody have any thoughts on this? Thanks!

I've never heard that IBUs are perceived bitterness.
In fact, there are labs that test IBU levels.

Ya i'm a bit foggy on that myself. I've also read about the mechanized, standardized testing but then have also come across this little nugget on the wikipedia page for beer measurement under the bitterness section...

"The bittering effect is less noticeable in beers with a high quantity of malt, so a higher IBU is needed in heavier beers to balance the flavor. For example, an Imperial Stout may have an IBU of 50, but will taste less bitter than an English Bitter with an IBU of 30, because the latter beer uses much less malt than the former."

Then again, that's just wikipedia, so who knows?
http://en.wikipedia.org/wiki/Beer_measurement

They're different beers. From the North Coast website on anniversary version: "[blah blah lots of great stuff] make it a worthy tribute to Old Rasputin."

And, they must be using some kind of chemical test, or at least a calculation based on the AA% of their hops, to come to 79 IBU's on the original. 79 is a hoppy pale, or a sessionable IPA, which are way more subjectively bitter-tasting than the smooth roasty goodness that is Old Rasputin.

Hmmm. Ya. Thanks for your thoughts. I suppose the best way forward is to brew an OR clone, add bourbon soaked oak to the secondary, hope for the best and tweak it from there...??

IBU's are based on mg of alpha acid per liter of liquid (beer). It has nothing to do with how the bitterness is perceived. They probably add less bittering in order to accentuate the oak character of the beer. I'd say just reduce the bittering hops in the clone recipes to get the proper IBU's and oak age from there.

humm, having brewed a great clone of "old rasputin" this sounds like one I should look into...

If the anniversary is higher in alcohol and lower in IBU's then that makes sense as mentioned, in higher gravity beers the hops are not as efficient in the boil. Here is where math comes in handy but with brewing software out there you can simply plug in the clone recipe then look at the malt percentages and start ramping them up until you get the gravity you need for 11.9 percent alcohol. Keep an eye on the IBU's because they will start decreasing as the malt bill gets higher. Once you have achieved the proper OG then raise or lower the hop bill to get their advertised IBU level. This should get you pretty close.

Thanks for the great advice everyone!

Tootal - that definitely sounds like a good way to go.

Dracus - any chance you'd post this great recipe of yours??

Still_dreamin said:

.. Dracus - any chance you'd post this great recipe of yours??

Click to expand...

Seconded

Not that I have brewed it yet... But I took the BYO Old Rasputin recipe, converted it to AG, bumped the grain bill to 1.100 to get 11.4, and I changed the hop bill to 40 IBU's. SxS sampling will happen probably September 2014. If it is close, then great! but, if its different I hope its at least good to finish without leaving it to sit for two years.

Here is my all grain adapation of the BYO rasputin recipe

SRM: 36.0 SRM SRM RANGE: 30.0-40.0 SRM
IBU: 63.7 IBUs Tinseth IBU RANGE: 50.0-90.0 IBUs
OG: 1.087 SG OG RANGE: 1.075-1.115 SG
FG: 1.019 SG FG RANGE: 1.018-1.030 SG
BU:GU: 0.732 Calories: 332.2 kcal/12oz Est ABV: 9.1 %
EE%: 66.00 % Batch: 5.50 gal Boil: 7.92 gal BT: 60 Mins


Total Grain Weight: 19 lbs 12.0 oz Total Hops: 4.25 oz oz.

Amt Name
16 lbs Pale Malt, Maris Otter (3.0 SRM)
1 lbs 4.0 oz Caramel/Crystal Malt -120L (120.0 SRM)
12.0 oz Chocolate Malt (350.0 SRM)
8.0 oz Brown Malt (65.0 SRM)
8.0 oz Caramel/Crystal Malt - 20L (20.0 SRM)
8.0 oz Caramel/Crystal Malt - 40L (40.0 SRM)
4.0 oz Black Barley (Stout) (500.0 SRM)


Name Description Step Temperat Step Time
Mash In Add 26.00 qt of water at 163.1 F 152.0 F 60 min

Hops?

Ohhh my the hops got left off...

2.50 oz Cluster [7.90 %] - Boil 60.0 min Hop
0.50 oz Northern Brewer [8.50 %] - Boil 60.0 min Hop
0.75 oz Centennial [8.50 %] - Boil 2.0 min Hop
0.50 oz Northern Brewer [8.50 %] - Boil 2.0 min Hop

Yeast?

Wlp 100 American ale. I made a starter per Mr malty.