Ask the Experts

Homebrew expert Brad Smith, author of the Beersmith homebrewing software and the voice behind the Beersmith podcast, tackles questions about hops additions, conical fermentors, and kegging beer.

What are the differences among bittering, flavor, and whirlpool hops? How can a homebrewer do a whirlpool addition?

As little as 5 years ago, brewers primarily used three types of hops additions for making beer: bittering, flavor, and dry hopping. Bittering additions were added early in the boil to provide the bulk of the bitterness needed to balance the beer. Flavor additions were done late in the boil, usually at 20, 15, 10, or 5 minutes from the end of the boil. These were intended to provide more flavor and aroma than boil additions. And finally dry hops were added late in fermentation, not to provide bitterness but to add fresh hops aroma to the beer.

Over the past few years, our knowledge of hops aroma oils and how they contribute to beer aroma and flavor has expanded dramatically. Scientists have isolated dozens of hops oils including myrcene, linalool, gerianol, caryophyllene, humulene, and farnesene. We’ve also learned that these aromatic oils are extremely volatile, which means the bulk of the oils

will boil away in as little as 10–15 minutes in the boil. The net result is that we now understand that boiling hops, even for a short period, does not preserve the flavor and aroma we most want to preserve in beer. The former “flavor” additions don’t add much flavor; they primarily contribute bitterness, which of course can be more efficiently done with a bittering addition. Whirlpool and dry-hop additions done below boiling temperatures do a much better job of preserving desirable hops oils.

The net result of this new knowledge is that modern hops schedules for hoppy brews such as IPAS consist of bittering, whirlpool, and dry-hop additions, but not flavor additions. The boil/bitterness addition provides the bulk of the bitterness, and the whirlpool and dry-hop additions preserve the critical aromatic oils. Whirlpool additions are usually added shortly after flame-out while the wort is still hot (typically at 168–194°F/75–90°C). On a commercial system, these are done in

the “whirlpool” system after the boil, which helps separate the wort from hops and grain materials. Homebrewers also commonly refer to “whirlpool” hops as hops added to the wort after the boil but before the wort is chilled. A homebrewer would typically add whirlpool hops to the kettle and let them steep for 10–20 minutes before the wort is chilled and transferred to a fermentor.

I see a lot of homebrewers switching to conical plastic or stainless-steel fermentors. Do I need a conical fermentor to make good beer?

A conical fermentor has a cylindrical main fermentor attached to a conical bottom. The cone is typically set at around a 60° angle, which allows any sediment or yeast to slide rapidly down the cone and settle in the bottom. This leaves minimal contact between the sediment and beer and makes it easy to draw the sediment/yeast off the bottom using some kind of dump valve at the bottom of the cone.

A conical fermentor is what professionals call a “unitank,” in that every stage of fermentation can be completed in the same vessel (primary, secondary, tertiary, clearing/aging) without needing to transfer the beer from vessel to vessel. Yeast can be harvested for reuse from the bottom of the tank, and typically, every few days the sediment is drawn off so it will not affect remaining beer. Commercial conicals also have temperature control for precise fermentation profiles.

Home conicals have the same advantages: You can ferment and age beers for an extended period in the same vessel without transfers, and you can harvest yeast easily and keep your beer separated from sediment. Lower-priced plastic conicals have collection balls for harvesting yeast, thermo-wells to monitor temperature, and are priced competitively. Higher-end home stainless-steel conicals have similar features and often add separate racking valves, and some have optional temperature-control systems. Some larger ones can also be pressurized for low-pressure oxygen-free transfers using a CO2 tank.

All of that being said, a conical is not required to make great beer. In fact, you can ferment great beer in a cheap food-grade plastic bucket as long as you use proper sanitation techniques. You can certainly separate your beer from sediment by just racking it to another vessel, and you can harvest yeast from the bottom of your bucket or carboy. A conical just offers some time savings, less risk during transfers, and ease of use, particularly for larger batches (10 gal/38 l or larger), where it becomes harder to lift and transfer large volumes of beer.

I’m thinking of switching from bottling my beer to kegging. What do I need to begin kegging beer?

Kegging beer offers a huge time savings versus bottling. Stainless-steel kegs are very easy to clean, and you can force carbonate your beer, which gives you better control over the exact carbonation level. The only downside is that you do need some kind of refrigerator—either space in an existing refrigerator or a dedicated freezer/refrigerator or kegerator to store the keg because proper serving pressure requires refrigeration.

Craft Beer & Brewing Magazine® has a great class on kegging your beer (see learn.beerandbrewing.com), but here are

the basics. The most basic system consists of a keg, a CO2 tank and regulator, two hoses with connectors, and a simple plastic picnic tap. The most popular kegs are 5-gallon (19 l) Cornelius (soda) kegs, which are about the size of a scuba tank, though 2.5- and 1.5-gallon mini-kegs are good options if your refrigerator space is limited. Kegs may have either ball-lock or pin-lock connectors, which refers to the style of connector used on the in and out ports of the keg.

A CO2 tank provides carbon dioxide gas to carbonate and also dispense your beer. CO2 will not spoil your beer the way oxygen will, so a Co2-pressurized keg will store for many months. Most beginner kits come with 5 lb (2.3 kg) CO2 tanks, and they are shipped empty. You can fill or exchange the CO2 tank at your local beverage-gas supplier. For a small additional fee, you can usually upgrade to a 10 lb (4.5 kg) or 20 lb (9.1 kg) tank, which will last a lot longer and is generally about the same price to fill.

You will also need a pressure regulator attached to your CO2 tank. The regulator lowers the pressure from roughly 800 pounds per square inch (psi) to a typical beer-serving pressure of 11–13 psi. A gas line connects from the regulator to the input on the keg to pressurize the keg. The output of the keg connects to a beer line that runs to the tap. Most beginner kits come with cheap plastic “picnic” taps (at right), though you can also purchase stainless-steel pub-style taps to install on your refrigerator door or bar.

To use your keg system, first assemble it and check for leaks by applying pressure and spraying the various fittings with Starsan or soap/water, which should bubble if a leak is present. Clean and sanitize your keg and then siphon your finished beer into it. Once the keg is full, seal it up and apply CO2 pressure. Use the purge valve at the top to purge the oxygen from the keg and replace it with CO2. To carbonate the beer, put the keg in the refrigerator and set the pressure to about 12 psi. If you leave it under pressure and refrigerated, the beer will fully carbonate within 5–7 days. After that, just serve and enjoy!

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