Hops are a backbone ingredient in beer. They are the preservative and they balance the malt sweetness. They add flavour and aroma.
Over the past decade the use of hops in may craft beers and many home brew recipes has steadily increased. Big beers with big hops have become very popular, and the trend doesn’t seem to be slowing down.
So, how are the hops used? How does all that wonderful hop flavour and aroma get into the beer? Anyone who is a brewer will know that hops are added into the boiling wort, but is that the only way to do it? When I first leaned to brew my own beer I learnt about three places to put hops in beer: at the start of the boil for bittering, near the end of the boil for flavour, and at the end of the boil for aroma. That was basically it. This is the way that I leaned to brew and adding hops at these times have made some great beer. But the more hoppy beers I drank and the more hops I added to my brews, the more hops I wanted and the more I wanted new ways to add them.
So, a recap on the basics. Hops added at the beginning of the boil (typically at the 60 minute remaining mark) are used for bittering because the main bittering component, alpha acid, need to be isomerized (made soluble in water) by the boil and this takes time. In this long time in the boil, most of the essential oils and other compounds that make up flavour and aroma are boiled off and lost. Hops added near the end of the boil (10 to 20 minutes remaining) will impart flavour with little bittering (short boil time means less alpha acid is isomerized). Also, with the flavour addition, many of the aroma compounds are lost, but not all. With the aroma addition in the last 5 minutes of the boil, most of the volatile aroma compounds are saved and nearly no bittering is added to the beer.
That is the traditional home brew hopping schedule. In recent times many pro brewers and home brewers have been experimenting with some new (some old and newly rediscovered) methods of adding hops to beer. Here a few processes and devices are discussed:
Dry hopping is when hops are added to the fermenter, quite often in a nylon or mesh sack for easy removal. The hops are added after the beer has finished fermenting and are kept there for 4 to 14 days. The hops being added to the cool, now alcoholic beer leach their oils and other compounds into the beer, but add no bittering. This is a method of adding hop flavour and aroma. Generally the flavour and aroma is resiny and grassy in nature (good Northwest US hop flavours and aromas). Left for too long and a vegetable-like flavour can start to creep in (7 to 10 days seems to work best for me).
First Wort Hopping (FWH)
First wort hopping is done by adding hops to the boil kettle as the wort is first running in (this is generally an all-grain method, however an extract brewer could add hops to the wort before the boil and see some affect). This is done to give the beer a smoother bitterness and enhance the aroma. There is about a 10% increase in the bittering, however, being that the bitterness is smoother, the perceived bitterness is the same or maybe a bit less.
The theory is that the pH of the wort as it first runs into the kettle and the time with exposure to oxygen before the boil begins allow the compounds in the hops to oxidize to a more soluble state and are preserved in the beer throughout the boiling process. Not all the science is in on this, but experiments show that there is an enhancement to the finished beer’s aroma and the bitterness is not as sharp.
Mash hopping is when hops are added to the mash tun. This doesn’t appear to give any enhancements to bittering, flavour, or aroma and seems to be just a way to waste some hops.
To do a hop stand, hops are added after the boil is complete and the wort is still hot. The hops are allowed to soak in the hot wort for an extended time – 10 to 90 minutes typically, but it could be as long as over night. The main thing that is achieved with a hop stand is the kicked up flavour and aroma. Since the wort is not boiling, but hot, the flavour and aroma compounds are able to leach out into the wort and not be driven off by the boil. Since the wort is near boiling and the hops are left for some time, there is some bitterness that is imparted into the wort – estimates are 10-15% utilization (verse 35% in a boil).
This is sometimes referred to as “Whirlpool Hopping” because some brewers add the hops as they whirlpool the wort after the boil. The idea with whirlpooling the wort is to cause the turb to collect in the centre of the kettle (as it’s heavier material) so the clean wort can be removed. The hops are added while the wort is whirlpooled and the time of the hops stand is the time it takes to whirlpooled – same theory, just with a whirlpool.
Check out this article in Brew Your Own for more information.
Hop bursting is adding just a small amount of hops for a bittering charge (maybe as little as 5 IBUs) and a massive amount of hops in the last 10 minutes. The idea with this is the majority of the bittering comes from the late hops, but it also delivers a lot of flavour and aroma in the same shot. The small amount of “bittering” hops is just used to break the surface tension and prevents foaming during the boil. Because the bittering is coming from the late addition and not through a long boil, the bittering is softer and rounder then a traditional bittering charge. Also, some brewers report that hop bursting can increase the mouthfeel. There’s a great article on Mr. Malty about hop bursting.
The invention of continuous hopping is attributed to Dogfish Head brewery of Milton, Delaware. This is a process of adding hops to the wort throughout the boil in a continuous manner. Dogfish Head invented a machine to aid in this process called “Sir Hops-a-Lot” and has had great success in the continuous hopped IPAs such as their flagship 90-Minute IPA (continuously hopped for the 90 minutes of the boil).
By adding hops throughout the boil, the hops bitterness, flavour, and aroma all benefit with a depth of character. This process is labour intensive without Sir Hops-a-Lot, or some similar machine, but by not just adding a few additions, the beer can get the full range of what the hops can offer.
A hopback is a sealed contained filled with hops that is put inline with the hot wort coming out of the kettle on its way to the fermenter. Because the hops are in short contact with the hot wort and is then quickly chilled, the aromatics are preserved. This has a duel-purpose by not only adding to the hop aroma, but also acting as a filter for the wort coming out of the kettle.
This is a device that a home brewer could McGyver at home. See this design from BYO.
Created by Dogfish Head, a Randall is used as part of a draft beer system. It is a canister that is filled with hops (or spices, or anything else that you’d like to infuse into the beer). The beer runs though the hops (or whatever) on its way from the keg to the glass and is infused with the flavour and aroma.
As Sam Calagione, founder of Dogfish Head, said about the Randall:
“Randall the Enamel Animal is the original gangster organoleptic hop transducing module. Basically, it’s a sophisticated filter system that allows the user to run draft beer through a chamber of whole leaf hops, spices, herbs, fruit, etc. so that the alcohol in the beer strips the flavour from whatever you add and puts it in the beer.”
A Torpedo is an invention of Sierra Nevada of Chico, California. It is a column that is filled with hops and connected to the fermenter. The fermenting beer is circulated through the Torpedo as an alternative to dry hopping the beer. By circulating the beer the brew master is better able to control the imparted flavours and aroma and better utilize the hops by ensuring proper contact with the beer.
Sierra Nevada has had great success with their Torpedo Ale, even naming their new tasting room in Berkley, California the Torpedo Room.
So, here’s to hops and the ever inventive brewer. ~ Cheers!