Hop Stands & Hop Bursting: Tips from Pros

A hop stand sounds like something you’d do with your car at a stop sign, while hop bursting conjures up images of flowers exploding in defense of being harvested. In actuality, both terms relate to methods of hop utilization occurring once the flame has been turned off. Two hop experts share their thoughts on the subject.

Curt Plants, Head Brewer at GoodLife Brewing Company in Bend, Oregon. GoodLife is Bend’s newest brewery. And although they opened in mid 2011, they have already increased capacity by more than 60% with the addition of new 30-BBL and 120-BBL fermenters. GoodLife brews Descender IPA and The Rescue Pale using a “hopbursting” technique.
The hop stand is different than hop bursting, though they kind of relate in the same way. Hop stand is basically just letting your hops sit on the wort for a period of time. It can be 10 to 90 minutes depending on where it sits on the wort. It is not boiled.

Hop bursting is a technique where the brewer uses 95 percent or all of the hop additions in one single addition at the very end of the boil or during the whirlpool to pull as many flavor and aroma oils out of the hops while simultaneously not allowing the alpha acids to completely isomerize and vaporize the oils. We achieve almost all of our IBUs through this method, while maybe adding a small amount of hops at first wort or 60 min addition in our beers above 50 IBUs.

At temperatures of 175 °F (79 °C) and above you achieve a lot of isomerization of the hops alpha acids. Our theory is that we don’t want to get a very bitter beer; we want a flavorful and aromatic beer. Adding the hops in the whirlpool will achieve 15 percent utilization on the bitterness side, but all the oils and compounds will remain in the wort on the way to the fermenter to achieve as much flavor and aroma as we possibly can.

At that stage (homebrewers) are pulling about 10 percent utilization. A lot is going to depend on the temperature. If it’s at boil temperatures you’re going to get a lot higher utilization, but as it cools that number starts to go down. When the temperature gets below 175 °F (79 °C) you’re no longer isomerizing the alpha acids. That’s really a temperature we try to get down to in the hop burst so we can start pulling those oils rather than boiling them off and turning them into bitterness compounds. Above 175 °F (79 °C) you’re still getting a lot of aroma compounds as well. It depends how long they sit there.

We add our hops in the whirlpool as late as we can, about three-quarters of the way through. Since we want to get the hops off as fast as we can, we have a 20-minute rest in the whirlpool to get a good trub pile, then we start our knock out to the fermenter. We have a cold jacket that runs though our wort to cool it down and get it out of those high temperature ranges, allowing us to get more aroma and flavors into the beer. Don’t let hops sit too long in the whirlpool.
There are formulas (to calculate utilization) out there, but they are not exact. It’s better to throw in three times the amount (of hops). Trial and error is the best way. With normal utilization in the boil you get 30–35 percent utilization (for bitterness), but with hop bursting you get 10 percent utilization. So you’d need to add about three times the amount of hops in the whirlpool to achieve that bitterness level. But, all those flavors and aromas will pop through for a more flavorful and aromatic beer.

There are side effects to this practice. Your yield is going to go down because you’re using more hops; less wort at the end. You might also pull some grassy compounds, depending on the hops you use. Noble-type varieties aren’t necessarily best in hop bursting as you pull a lot more grassy notes and you could end with a really astringent beer. Aromatic varieties are mostly what we use: Amarillo®, Centennial and Chinook. Be sure to get a nice malt to go with it otherwise you get a really unbalanced beer.

This method is also expensive because you use three or four times more hops than a normal brew.

Mitch Steele, Head Brewer and Production Manager at Stone Brewing Co. in Escondido, California. Before coming to Stone, Mitch worked as the Assistant Brewmaster for Anheuser-Busch’s Merrimack, New Hampshire facility. He is the author of IPA: Brewing Techniques, Recipes and the Evolution of India Pale Ale (Brewers Publications, 2012)

The way our hopping process works at Stone is that we do one hop addition at the start of the boil for bittering, then add all of our hops in the whirlpool and transfer the wort on top of the hops. This is the first brewery I’ve been at that’s done things that way. It’s a pretty good technique because you are getting a ton of hop aroma, but we’re also getting more bitterness then we initially accounted for. We’re seeing anywhere from 15 to 20 percent utilization with whirlpool hop additions. It surprised us — we thought it would be in the single digits, but it’s pushing 20 percent.

The bottom line with this type of hopping is if the hops go in late they stay there until the wort is out of the vessel. They are going to be in contact with the hot wort for about an hour. We have a 15-minute rest and then it takes about 45 minutes to knock the wort out.

If you try this type of late hopping at home, you’re going to get more flavor extraction the longer the hops sit in there, but there is a point when (the flavors) start going south on you, so don’t leave them too long. Try experimenting with different lengths of time and hops.
The whole hop bursting technique is something we’ve been playing around with and I think it has a lot of potential. You’re loading up on the back end of the hopping and not boiling for a long time, but you’re still extracting the bitterness.

One way (homebrewers) can do this on a small scale is with a hopback. If you have one, you can just run the wort through a hopback and then you get exposure to the hops just for the time it takes to run the wort through. But you’re going to get a different result then if you added hops to the whirlpool and just leave them in there like we do here at the brewery.

Issue: May-June 2013