Hop Stand Experiment (3/5/13)

Over the past decade or so, brewers have tried to find more and more places in the brewing process to add hops. The latest innovation has been adding hops to the whirlpool. A whirlpool is a container that collects sediment in the center of a circulating vortex, allowing the brewer to remove much of the hop debris and malt proteins from her wort.

The wort is at about 200F during in the whirlpool, which typically lasts 30-90 minutes. Since commercial breweries brew on such a large scale, there is not much temperature loss over that time. Adding hops at temperatures just below boiling allows the hot wort to extract different compounds than adding dry hops (which are added to the beer when it's at room temperature). Since the wort isn't boiling in the whirlpool, there is less loss of hop aroma with whirlpool hopping compared to kettle hopping.

Few homebrewers have the equipment to perform a true whirlpool, but we can emulate the effects of whirlpool hopping by doing a hop stand. To perform a hop stand, the brewer completes her boil, then adds hops and maintains the temperature of the wort for a certain length of time—say, 30 minutes. Like whirlpool hopping, a hop stand allows the hops to steep in hot—but not boiling—wort.

Homebrewers with immersion chillers have a lot more flexibility than commercial brewers, since we can chill their beer at any point in the process. Therefore, we don't have to perform a hop stand at 200F, like a commercial whirlpool. A number of homebrewers have experimented with cooler temperatures—i.e., under 180F—and have reported good results. The idea behind this variation is that lower temperatures will volatilize less of the aromatic hop oils. On the other hand, lower temperatures will also extract these hop oils less efficiently.

I decided to test the effects of different temperature hop stands by brewing a split batch of pale ale. Half the wort was subjected to a 200F (+/- 5F) hop stand for 30 minutes, mimicking a commercial whirlpool, while the other half received a 175F (+/- 5F) hop stand for 30 minutes. The hop stand was the only hop addition, with 3 oz in each (2.5 gallon) half. In addition to testing the effect of temperature on hop aroma, this experiment will also test the effect of temperature on alpha acid isomerization (i.e., production of hop bitterness), since I will be judging the difference in perceived bitterness between the two beers.

The beer itself is a fairly standard American amber ale, besides the massive hop stand. Mostly 2 row, with some Munich for malty goodness, Crystal 75 for caramel sweetness, and some flaked barley for body and head retention. The hops themselves are two of my favorites: Amarillo and Chinook. I've never used them as the only two hops in a beer before, but it is somewhat similar to the classic Amarillo/Simcoe combination that is used to great effect in beers like Alpine Duet and Ballast Point Sculpin. The sharp grapefruit/pine of Chinook enhances and balances the softer fruity/floral aroma of
Amarillo.

Results

Both beers were among the best I've ever brewed. As expected, the 200 degree hopstand produced a more bitter beer. When fresh, the 200 degree half was at a similar bitterness level as, say, Sierra Nevada Pale Ale. The 175 degree half was noticeably less bitter, and has been well received by both hopheads and those who don't normally drink hoppy beers. The 175 degree half also had stronger aromatics. As the beers aged, bitterness and hop aromatics both faded, and it became more difficult to tell the two apart.

As a result of this experiment, I now incorporate a big 175 degree hopstand in all of my hoppy beers. For IPAs, I also add a bunch of hops during the boil, while for pale and amber ales I stick with the no-hops-in-the-boil technique that worked so well in these beers.

Tasting Notes

Aroma: Pineapple, pear, jasmine, pine.

Taste: Toasted bread, sweet malt, more pear, grapefruit. Dry, but with significant malt flavor.

Mouthfeel: Light-to-medium bodied, medium-high carbonation.

Vitals:

ABV: 5.8%
OG: 1.053
FG: 1.010
IBUs: ???

Strike temp: 162
Mash in: 152
Mash time: 90 minutes
Batch sparge: 168F
Efficiency: 65%

Yeast: US05 (half packet in each half)
Pitching temp: 65F
Max temp: 70F

Malts Mashed		Amount	%	Max Pts.
2 row		8	71%	36.00
Munich		2	18%	36.00
Crystal 90		0.5	4%	34.00
Barley (flaked)		0.75	7%	32.00

Hops/Additions		Amount	Time	AA%
Amarillo		4	Hop stand	9.0%
Chinook		2	Hop stand	11.0%

This was my first time using water adjustments. The mash pH was a little high, so I added some lactic acid—unfortunately a bit too much! (My water has very low alkalinity and hence doesn't have much buffering power.) So I added 1.5 grams of chalk to balance it out, and ended up with a pH of 5.3. (Ideal mash pH is 5.3 - 5.5.)

3/8/13: The 175 beer is down to 1.010, while the the 200 beer is still at 1.014. Either the extra IBUs are having a minor inhibitive effect on the yeast, or the fact that the yeast for the 200 beer sat in the rehydration water for an extra 30 minutes slowed it down. At this point, the 175 beer is more aromatic and much less bitter (maybe 25 IBUs, versus 40 IBUs for the 200 beer). If I brewed this again, I'd roll the Munich back to 10%.

3/12/13: The 175 beer is at 1.008, and the 200 beer is at 1.009. Both taste great, but the 175 beer still has better aroma and less bitterness.

Bottled 3/16/13:
#3 = 200
#4 = 175

4/2/13: Minor disaster. Accidentally bottled with fake bottle caps (no seal). Bottle primed and re-capped.