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| Extract & Hop Extraction: Mr. Wizard |
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| The wise one answers your brewing questions. |
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Dear Mr. Wizard,
I've read that with the Texas 2-step and late extract methods that you will get better extraction of hop bitterness if the wort is less dense. Also, from the late extract method, it sounds like the full 60-minute boil isn’t necessary for most malt extracts . . . just the last 15 minutes to sanitize it before cooling the wort. So my question is: Can you hold off the addition of malt extract (in an all-extract or partial-mash recipe) until the end of the boil? And then, taken to an extreme, can you just boil the hops in plain water in some smaller volume (like 1 gallon or 3.8 L) in an all-extract recipe, or does something else in the wort (like pH levels) play a part in extracting bitterness from hops?
The root of my question is whether or not I can boil less wort, as this would require less energy to maintain a vigorous boil with a normal kitchen stove.
Patrick Louie
San Francisco, California
The Wizard replies: This question really shows me how homebrewers have changed since the early days of the legal homebrewing movement in the United States. The early pioneer homebrewers in the mid to late 70s wanted to brew beers with flavor since the selection of domestic products on the market had reached an all-time low; the last thing a pioneer homebrewer wanted to do was look to commercial brewers for ideas. Things have changed dramatically in the last 25 years and the idea of a technologically advanced brewery no longer implies yellow, flavorless barley pop.
The Texas 2-step was developed to address space issues many homebrewers have on their stoves by boiling normal strength wort (as opposed to low volume, high strength followed by dilution) in two 2.5-gallon (9.5-L) batches over two days to end up with 5 gallons (19 L) of wort. As Chris Colby mentioned in his article in October 2003 most medium and large commercial brewers add more than one batch of wort to a fermenter for economic reasons . . . not too different than homebrewing, as we would all probably install a professional Viking stove with six gas burners if it would fit in the house and within the budget!
The late extract method was designed for partial mashers and suggests boiling the small volume of homemade extract with hops for about 45 minutes and then adding the dry or liquid malt extract to bring the gravity into check during the last 15 minutes of the boil. This method also appeals to the homebrewer who cannot easily boil large volumes of wort and who does not want to boil highly concentrated wort. The reason most seasoned brewers wish to avoid boiling concentrated wort and diluting later with water is that color and flavor are sacrificed and hop utilization goes down. When the concentrated wort is diluted to the desired original gravity, it is usually different from its counterpart boiled at a lower concentration and with all the required water in the kettle from
the beginning.
The method you suggest is not new and a version of this practice is unknowingly used by many homebrewers. Your idea is to essentially skip wort boiling, except for a few minutes for wort sterilization. And the hop bitterness and flavor would be added from a little pot of boiling water and hops. The idea reminds me of cooking where the dish comes together from a variety of little side projects happening all at once on the stove top. This is actually how most hopped malt extracts are made, except the hops are not boiled in a little kettle in the corner of the plant; they come in a can from a hop extract plant!
This is where most homebrewers get “turned-off” to what happens in the commercial arena. The idea of adding hops from a can just seems too mechanical. If a brewer then wants hop aroma, another can or bottle is pulled off the shelf and a few drops added for bouquet. There is a reason, however, that hop extracts come from specialty companies — extract production involves much more than boiling a fist full of hops in a pot of water.
Hops contain hundreds of components and about three classes are of most interest to brewers: polyphenols, bittering acids and the aromatic oils. Polyphenols or tannins react with proteins during wort boiling and aid in trub formation. Some survive into the finished beer and can add a grassy character if present in highly hopped beers. The bittering acids in hops have a very low solubility
in aqueous solutions, e.g., wort and beer,
and isomerize during boiling into iso-alpha acids that are water-soluble. Finally, there are the oils in hops that lend piney, citrusy and spicy aromas to beer.
When hops are added to wort and boiled the pH is around 5.2 and there is protein present to precipitate much of the polyphenols extracted from the hop leaf. Boiling time is important and most beers that have hop aroma use late additions. During the boil, hop acids undergo numerous chemical changes and the resultant mix has a profound influence on beer bitterness and the quality of bitterness. When the pH of wort boiling is increased by adding alkaline buffers, hop utilization increases but bitterness is reportedly unpleasant. If you boiled hops in water as opposed to wort, the pH would be higher and the flavor would lack.
Commercially produced hop extracts are made by extracting the acids and oils from the plant material. Acid extracts can be bought and added to the brew kettle like whole hops or pellets. Isomerized extracts are also avalibale and are made by isomerization under controlled conditions so that the mixture of compounds is not too different than that seen during traditional wort boiling. Isomerized alpha-acid extracts can then be added to wort or beer to impart bitterness. Isomerized alpha-acids can be further treated using sodium borohydride (a strong reducer) to produce light-stable extracts that are immune to skunky flavor when beer is packaged in green or clear glass bottles. All hop extracts are extremely concentrated and must be measured carefully.
Hop oils are typically fractionated to separate the oils into different classes of compounds. Oils are frequently sold with descriptors such as “late hop aroma” and “dry hop aroma” to give brewers an idea of the qualities the oil should impart to beer. In the early days of extract production, acids and oils were separated with solvents such as hexane but the industry has completely switched to liquid and supercritical carbon dioxide extraction methods.
Suffice to say hop extract and oil production is a high tech venture. Most of the hop chemistry experts in the world have advanced degrees in some type of chemistry and think about hops completely differently than the practical brewer. Luckily, their products are available for brewers to easily and conveniently use.
You can have all the creative freedom as all-grain brewers by using unhopped malt extracts, assorted specialty malts, the yeast of your choice and hop extracts for bitterness and aroma. This method could be morphed with the late extract method to produce 5-gallon (19-L) batches of wort with small pots and would avoid the complexity of producing your own hop extract.
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Your First Brew
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Brew Spreadsheet
Calculate your recipes before you brew with this handy spreadsheet program!
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Brew Water Spreadsheet
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