Roosterfish Brewing  Hop Warrior

Style: Double IPA 
Color: dark orange-amber
ABV: 8.7% 
Price Point: $7 for 22oz 
Technical Notes: OG 1.081    TG 1.015    Color 14.68  IBU 120.2

Hedonic Notes:

The pour is a slightly hazy orange amber color with a light caramel colored crown of foam.  The bubbles fade quickly, but the beer remains somewhat effervescent.

Citrus hop notes form the bulk of the aroma with a great deal of lemon and grapefruit.  Some grassy notes and a very strong sweet caramel malt backbone.  A bit of alcohol solvent aroma rears its head as the beer warms.

At first, the flavor is of strong sweet malt.  A strong American-style Cascade-like bitterness follows.  The citrus notes that are present in the aroma are backed up by a strong piney bitterness , but the grass flavor does not appear as much, or is perhaps  overwhelmed.  The beer is quite bitter, but the malt is strong enough to balance it and make the beer drinkable despite the alleged 120+ IBUs.  The beer finishes quite clean with a nice lingering citrus note.

After the very strong sweetness and high bitterness, one might expect a viscous and dry {mouthfeel}.  Such was not the case, as the beer was very well-balanced and felt medium-bodied.

For being 120+ IBUs, the beer does not taste overwhelmingly bitter and is perhaps almost easy to drink.  There isn’t too much in the area of earthy or spicy hop notes, but that is permissible in some American double IPAs.  One nice feature of this, however, is that it will pair well with spicy foods that have earthier flavors—ribs perhaps.  Overall, it is an enjoyable experience, but it is very difficult to compete in the American double IPA category these days.  Indeed, with everyone making their own extreme IPA, it’s difficult to stand out in the category.

Rating:  3 out of 5 corks .

Crystal structure of barley alpha amylase from PDB entry 1AMY.

The mashing process hinges on the activity of two enzymes: alpha amylase and beta amylase (genes named AMY1 and AMY2 respectively, among other isoforms).  These two enzymes break down complex starch structures into simple sugars.  By controlling the precise activity of each enzyme, one may plan a specific sugar profile for a beer, producing flavors ranging from complex and sweet to straightforward and alcoholic.

Beta amylase has the ability to break nonreducing alpha 1,4-glycosidic linkages.  Thus beta amylase yields maltose (dimmers) or maltotriose (trimers).  Yeast are not able to metabolize maltose and maltotriose quickly, and this results in a sweeter beer and a thicker mothfeel.

Alpha amylase may cut any alpha-1,4 glycosidic linkage, ultimately leaving sugar monomers.  These monomers are easily metabolized by yeast, leaving a crisp taste with a higher alcohol content.  An important function of this enzyme is that it is able to cleave beta amylase products into even simpler sugars.  Check out PDB’s February 2006 Molecule of the Month feature on amylase.

A barley stalk thanks to net_efekt at Flickr. Also, check out net_efekt's discussion of barley types.

Each enzyme operates optimally at a slightly different temperature, allowing the brewer to precisely plan the beer’s texture and flavor.  Beta amylase operates optimally at 60C to 65C while alpha amylase sees optimal activity at 72C to 75C.  Both enzymes are irreversibly denatured above 80C, leaving no activity.  By selecting mash temperatures and times within these ranges, a brewer can control the beer’s taste.

Both enzymes bind and unbind randomly, leaving chains of random lengths.  At first, the enzymes tend to diffuse between large chains, but as the chains become smaller, the enzymes tend to break the smaller portions more quickly since they diffuse to the active site more readily.  Indeed, this is a common feature of enzymatic systems and a challenge in a similar system: breakdown of cellulose for biofuel production.

Amylase enzymes work by using water to hydrate the glycosidic linkage (hydrolysis) and leave two stable sugar ends.  The resulting chains both have hydroxyl groups in a conformation identical to the bond that linked the sugars previously.  Check out this great animation from the University of Indiana.

Chapman, Pallas and Mendicino.  ”The hydrolosys of maltodextrins by a beta-amylase isolated from the leaves of vicia faba”  Biochimica et Biophysica Acta – Enzymology. 1972.

Fix, George. Principles of Brewing Science.  Brewers Publications: Boulder, CO.  1999.

Kadziola et al. “Crystal and molecular structure of barley alpha-amylase” Journal of Molecular Biology. 1994.

Svensson.  ”Protein engineering in the α-amylase family: catalytic mechanism, substrate specificity, and stability” Plant Molecular Biology. 1994