Often while doing HIV research I need to repeat an experiment. Not only do I make sure that a result is not a fluke but there is an opportunity to better the experiment by adding more controls, more samples, etc…, to get a more meaningful result. I learn more by repeating the experiment in small ways. The same holds true for brewing beer.
Part of brewing is repeating the same batch in order to improve your technique. In this case, I brewed an American IPA last year that I was not happy with and it suffered in score during a homebrew competition. The major complaint was a phenolic character, however my impression of the fault was an astringency that gave the beer some harsh notes. I suspect this could have been due to the hopping but its hard to tell. Here is where I possibly went wrong with the beer:
- Fermentation temperatures fluctuated wildly. Pitched at 61°F but it jumped to 73°F on the second day due to an active fermentation. Brought it back down 64°F but it ramped up to 68°F.
- There was significant hop trub in the fermentor. In trying to collect enough wort, almost 50% of the hop debris from the kettle made its way into fermentation.
- Hopping schedule was off. I either used too much hops, or I selected for a hop varietal that was pretty harsh.
- Recipe design was flawed.
Of these options I think #1 and #2 are probably the culprits, with the huge swings in fermentations temps probably being the biggest contributor. In brewing beer, pro or amateur, controlling temperature of fermentation is critical. Wild swings (even as little as 5°F) will cause a change in yeast metabolic activity and they will begin to secrete compounds into beer that would be considered off-flavors. For me, temperature control has always been a problem since I can’t fit another temperature controlled refrigerator in my small Bronx apartment. This is the main reason I tend to brew by the seasons, mostly in the winter for strong ales and saisons in the summer.
As for the hop trub being present in the fermentation, it definitely can have effect on the beer though there is some debate as to how. Some say there is no difference, while other brewers say the opposite. Brewer’s yeast has the ability to bind minute hop material and thus alter its flocculency. This change could be enough to change the metabolic profile of the yeast and produce off-flavors.
As for reasons #3 and #4, I doubt that they had an impact on the beer. I’ve known plenty of other brewers (pro and amateur) that use more hops than I did. I also feel the recipe design was pretty solid, focusing on a simple malt profile that would give me great attenuation.
To fix the temperature problem I assembled an easy system to keep my beer cooled. I used an empty rubbermaid bin and filled it with about 4 inches of ice-cold water. I then placed my fermentor in the bin wrapped in a towel with a fan directly aimed at the carboy. The towel acts like a wick and as water travels up it evaporates with help from the fan. Any heat generated from the yeast gets transferred to the towel and evaporates along with the water. I keep the water cool by changing out two frozen water bottles, twice a day. With this protocol, the beer stayed at a constant 64°F. As for the hop break I had a simple solution. I scaled up the recipe by a gallon and left about a gallon of trub and wort in the kettle.
The recipe (6 gallon batch):
- 10 lbs of Pale Ale malt (Briess)
- 3 lbs of Munich malt – 10L (Briess)
- 1 lb flaked wheat (Briess)
- 6.7 ozs of Crystal malt – 20L (Briess)
- 6 grams of Gypsum (Calcium Sulfate)
Mashed in at 152°F and held at this temperature for one hour. Increased temperature to 168°F for mashout, vorlaufed, and batch sparged as usual. Collected 7 gallons of wort at 1.054 with a mash efficiency of 72%. Boiled and added:
- 1 oz of Chinook (11.2% AA) at 60 minutes.
- 0.5 oz of Centennial (8.8% AA) at 20 minutes.
- 1 oz of Centennial (8.8% AA) at 10 minutes.
- 1 oz of Simcoe (12.2% AA) at 5 minutes.
- 0.5 oz of Simcoe (12.2% AA) at flameout.
- 0.5 oz of Cascade (5.5% AA) at flameout.
- 1.0 oz of Centennial (8.8% AA) at flameout.
- 1 oz of Simcoe for dry-hopping.
- 1 oz of Cascade for dry-hopping.
- 1 whirfloc tablet (15 minutes)
- 1/2 tsp of yeast nutrient (15 minutes)
Cooled by immersion chiller and whirlpooling to 76°F and transferred wort to ice bath – cooled further to 64°F. Pitched a total of 300 billion cells of Wyeast 1056 and Wyeast 1764 (Rogue’s Pacman strain) and aerated with pure O2 for 30 seconds.