Hops and a Brush with Fame

Last Friday (March 26), webmaster Rick and I traveled to Stowe, VT, for a conference on hop-growing. We were accompanied (actually driven!) by Rick’s friend Rose, who was involved in the planning of the conference and got us invited… The conference was sponsored by the University of Vermont Extension, and gathered together farmers, brewers and others interested in hops and beer. With the growing interest (no pun intended) in locally-sourced foods, it’s only natural that brewers would also like to have local sources for their ingredients. UVM’s project is to try to grow barley and hops in Vermont, for Vermont breweries. Similar projects are underway in other states as well.

There were three featured speakers: Rick Pedersen, a farmer from Seneca Castle, NY, who has about 10 acres of hops along with his vegetables and livestock. He ran through a litany of all the things he has done wrong over the last several years in trying to grow hops commercially. Next up was Jason Perrault, a fourth generation hop-grower, breeder and developer from Yakima, Washington. He gave us a lot of botanical info on how hops grow, how they can be cultivated and developed as a business. Finally we heard from François Biron, a Quebec Ministry of Agriculture agronomist whose office is in its second year studying the feasibility of hop-growing in Quebec.

The conference was hosted at the Trapp Family Lodge – for the unaware, this is a hotel/resort perched on a hilltop above Stowe, with cross country ski trails, breathtaking views and first-class accommodations. And yes, it is connected to the Sound of Music – it was established by Maria and Baron Georg Von Trapp when they immigrated to the US. It is still in their family, a fact that was more than amply proven when, at lunch time, Rick, Rose and I were joined at our table by none other than Maria and Georg’s youngest son Johannes. He simply sat down, ate lunch with us, joined in our general conversation about hops, beer, etc… and told us all about his latest project at the resort, the establishment of an Austrian-style lager brewery.

After the featured speakers, the head brewer of the aforementioned brewery, Allen Van Anda, spoke to the conference briefly, explaining how they were brewing, the styles they were planning, and so on. We trouped down the road at the end and visited the brewery with Allen and the Lodge’s Director of Food & Beverage Jean-Luc Jenni…

Rick, Allen, Jean-Luc & the Guru - a virtual "Prost!"

admired (stared jealously is more like it) the gleaming stainless steel tanks and the oak barrels…

Old bourbon casks in which they are aging a doppelbock...

Unfortunately, they had not yet finished with all the paperwork necessary to actually pour us any beer. So we went away thirsty, but hopeful.

Unrelated to the conference, but a related topic: the first shoots of my hops are up, which for me is the truest sign of Spring. I will post pictures once they are clearly identifiable.

Hop rhizomes…

For readers in my local area, I have hop rhizomes available for sale at the South Royalton Market – these are root cuttings from Freshops in Oregon. There are 12 different varieties available, first come, first served. $5.29 per rhizome, limit 8 per customer, 2 of any variety… No shipping available, and we can’t set any aside for you, sorry! When they’re gone, they’re gone.

A Bitter Subject – Hops, aau’s, IBU’s, HBU’s…?

Caution: technical stuff and math follow!

What do you think when you see a beer recipe that calls for hops measured not in ounces but in HBU’s? or when you read a label and it tells you the beer has so many IBU’s? Ever notice on that packet of hops you bought at the Home Brew Store that the hops are rated based on aa%? What gives? How do you figure out how much to use? It’s not as complicated as it looks at first blush.

AAU’s and aa%: The relative bitterness of a given crop of hops is measured based on the acidity of the flower. The acid that brewers are primarily concerned with is the “alpha acid”, or aa – this is measured in a percentage, hence aa%. The higher the number, the more acidic and thus the more bitter the hop. The Hallertau I used this morning measured 3%, the Perle 6%, so the Perle were twice as bitter as the Hallertau. An AAU (alpha acid unit) is the product of the percentage of bitterness times the amount used – 1 ounce of those 3% Hallertau provides 3 AAU’s, one ounce of the Perle provides 6 AAU’s.

More common and relevant to the homebrewer is the HBU – Homebrewer’s Bitterness Unit – but it’s exactly the same thing as an AAU. If your recipe calls for 6 HBU’s of a given hop, work backwards. If you have a Chinook hop at 12% aa, you need to use 1/2 oz. to get 6 HBU’s (or AAU’s) – right?

IBU’s – International Bitterness Units – are the result of using the hop. There is actually an esoteric table which gives an indication of how bitter a beer will be based on how much of which hops are boiled, and for how long. So IBU’s are the sum total of all the hops added in a given beer, multiplied by a factor depending on length of boil and volume and strength of the wort. For more information on this, I recommend the excellent discussion in Greg Noonan’s “New Brewing Lager Beer”.

In a nutshell, the average homebrewer can use the following simplified tables, which I used in “North American Clonebrews”, although it is based on a table Greg devised for the “Seven Barrel Brewery Brewers’ Handbook”.

Assuming moderate/average strength wort, in a 5-gallon boil:

  • 0 minutes, or dry-hopping – .7
  • 5 minutes – .7
  • 15 minutes – 1.25
  • 20 minutes – 1.5
  • 30 minutes – 2.4
  • 45 minutes – 4.0
  • 60 minutes – 4.25
  • 90 minutes – 4.5

So one would multiply the HBU’s (aa% times ounces) times the above factors, to get the IBU’s.

If one boiled only one ounce of a 4.5% aa hop for 60 minutes, one would have 19.1 IBU’s (4.5 x 4.25)

But if one also boiled one ounce of a 2% aa hop for 5 minutes one would end up with 20.5 IBU’s (add another 1.4, or 2 x .7).

So work backwards – if you know the approximate IBU rating you are shooting for, it is relatively easy to calculate the amount of hops, the desired aa%, and the length of boil. At least I think it is…

Looking at the recipe I posted earlier for the Dortmund Export, we see a total of 22.5 IBU’s. 3.2 of that came from the first addition of Hallertau (.25 x 3 x 4.25); 12 from the 45-minute addition of Perle (.5 x 6 x 4); 5.4 from the second batch of Hallertau (.75 x 3 x 2.4) and the last 1.9 from the final addition of Hallertau (.5 x 3 x 1.25).

So a quick quiz: If you boil 1/2 oz. of Galena at 8% aa for 90 minutes, 1 oz. Tettnang at 4% for 45 minutes, and dry hop with 1 oz. Saaz at 5%, how many IBU’s will the beer have? (Answer follows)

.5 x 8 x 4.5 = 18; 4 x 4 = 16; 5 x .7 = 3.5; total 18 + 16 + 3.5 =37.5 IBU’s.