Friday, June 5, 2009

Hopping Methods

Before I dive into the geekery, I'd like to announce that Rachel and I are parents! Our daughter was born last Sunday and words can't express how happy we are! Whoops, I think we just entered Extreme territory.

Back at the Craft Brewers Conference, I attended a seminar about maximizing hop flavor and aroma. The speaker was Van Havig, QA/QC manager of the Rock Bottom brewpub group, and his presentation detailed a company-wide experiment to assess the effectiveness of various hopping methods. Essentially, 30-some breweries produced the same baseline IPA recipe with varying late hopping procedures (yes, Miller's advertising department, we all add hops several times throughout the process). The experiment was loosely controlled, which was both good and bad. For example, differences in water treatments between breweries led to some interesting data. However, the fact that each brewery was allowed to use its own house yeast strain was - in my opinion - in direct conflict with the purpose of the experiment. Even with its flaws, the investigation was the most ambitious and informative of its kind that I've seen in the craft brewing industry.

For the experiment, each brewery utilized one of the following late hopping methods:

-Method 1: add 1 lb/bbl of hops at the end of the boil.
-Method 2: add 1 lb/bbl of hops at the end of the boil and wait an extra 30 minutes before cooling.
-Method 3: add 1 lb/bbl of dry hops after primary fermentation.
-Method 4: add 0.5 lb/bbl of hops at the end of the boil and wait an extra 30 minutes before cooling, then add 0.5 lb/bbl of dry hops after primary fermentation.

Mr. Havig used formal sensory evaluations, laboratory tests and statistical analyses to determine the impacts of the various methods. Here are some highlights:

-Methods 2 and 4 tied for the strongest hop flavor, which implies (1) that brewers can reach a point of diminishing return with kettle additions and (2) that hot residence time increases hop flavor.
-Methods 3 and 4 tied for the strongest hop aroma, which implies that brewers can reach a point of diminishing return with dry hopping.
-There were significant positive correlations between perceived bitterness, perceived hop flavor and perceived hop aroma.
-The correlation between perceived bitterness and measured IBUs (International Bitterness Units) was insignificant, which implies that our senses measure bitterness differently than industry-standard lab methods.
-There was a significant negative correlation between perceived hop character (flavor, aroma and bitterness) and sulfate concentration, which directly opposes the "Burtonize your water for hoppy beers" theory.

Being the good pseudo-scientist that I am, I decided to brew a Summer IPA using some of these new hypotheses. Here's what I did:

-Raised my water's calcium content with primarily calcium chloride instead of calcium sulfate.
-Added about 65% of the beer's IBUs at the end of the boil.
-Allowed the wort to sit for 30 minutes before cooling (on my homebrew system, I usually start cooling immediately after the boil ends). With the high evaporation rates of most homebrew kettles, DME formation shouldn't be a concern.
-Added 0.5 lb/bbl of dry hops after primary fermentation.

The results: a clean and refreshing beer, but HOLY HOPS!! It blew my previous Pale Ale out of the water. I'm a convert.

The beer was destined for a wedding, so it required a label:

The wedding isn't until June 28th, but the beer is already on the road. Hopefully its massive hop character will pass the tests of time, travel and temperature swings!


Anonymous said...

That sounds yummy, I want some!

Steph Weber said...

Very interesting about sulfate concentration. We've been using gypsum in all our hoppy beers lately. Might have to do a little experiment of our own!

Your blog is great! My husband and I also plan to open a brewpub, though we're a few years behind you in the process (I've only written a small portion of the business plan). We're also both currently engineers! Seems like there are a lot of engineers-turned-brewers.

Keep up the good work here, I'm definitely going to read through what you've written so far, and hopefully pick up some pointers!

Joe said...

Hey Steph, thanks! Haha, years is right - at least for me. Because of you, I may be able to cross off "make a creme brulee" from my to-do list!

JohnW said...

"Raised my water's calcium content with primarily calcium chloride instead of calcium sulfate."

I have been toying with this after reading the presentation you mention. Could you fill some blanks for me so I can have a jumping off point for my own pale?

What did you raise the calcium to? 100ppm? If I do that with Chicago water, I get a really high chloride concentration. Did you use both gypsum and CaCl to get your calcium up without jacking up the Cl? What was your chloride concentration after your adjustment? Thanks! John

Joe said...

I added 150 ppm of gypsum and 250 ppm of CaCl2, which did the following:

Ca: 81 ppm -> 184 ppm
SO4: 15 ppm -> 99 ppm
Cl: 32 ppm -> 153 ppm

I try to keep my calcium level above 50 ppm, sulfate below 100 ppm and chloride below 150 ppm. The primary reason for me to add gypsum and CaCl2 is to lower my water's alkalinity. Once I reach my limits on sulfate and chloride, I'll usually remove the remaining alkalinity with lactic acid (or slaked lime, as long as it doesn't drop my calcium level to below 50 ppm).

If you need help figuring out acid/lime additions, check out the water calculation spreadsheet in the "File Cabinet" link near the top right of the main page. Feel free to shoot me an email about it too - my address is in my profile.

Mike Hartigan said...

Getting back to the hops - what did they do for bittering? Was this standardized, as well? Were the late addition the only flavor/aroma additions or were there others?

Joe said...

All of the beers were hopped with 2.8 oz/bbl of Nugget (12.5% alpha) at the start of the boil and 4.4 oz/bbl of Amarillo (8.4% alpha) 60 minutes into the boil. The third hop addition is the one that alternated between the four methods. Hey, the beer was triple hops brewed!

Mike Hartigan said...

Waiting 30 minutes before chilling is likely to cause DMS problems. How did they address that? (incidentally, rumor has it that RB waited 80 minutes, not 30 before chilling. How did they get away with this?)

Joe said...

Hey Mike, RB timed their last addition from the end of the wort transfer into the fermenter. One recipe added hops 50 minutes from the end of knockout and the other was 80 minutes from the end, hence the 30 minute difference. The timing is pretty standard for commercial breweries. Both places I've worked at employed 10 minute whirlpools, 20 minute rests and transfers that took about 45 minutes. Neither brewery had DMS problems, nor did I get any in my homebrewery when I added a 30 minute hot rest after the boil. DMS is a concern in the sense that you shouldn't boil with a covered kettle or cool your wort with ambient air, but I don't think very many craft/home brewers actually know how long it takes for a significant amount of DMS to form (especially after a hearty amount of evaporation, which is hard not to achieve in a small brewery with a 60-90 minute boil).