British Brewer

Recreating the perfect British Pint

10 February


Hops Thought it was time for the next installment in our ingredients deep dive. So far we have covered water and the mighty yeast so I thought it was time to take a deeper dive into one of the more complex and underrated of all the ingredients in ale, hops.  I say underrated because hops do more than just provide the bitter flavour to balance out the sweet malt. Hops also contribute to the aroma and arguably more important have anti-bacterial properties that favor brewers yeast over bacterias keeping beers fresh and allowing a hopped ale to age without spoiling.

I have often wondered how hops came to be used in beer. I have to admit they are not an obvious choice.  Fermentation of fruit and grains has been an activity well documented in history going back into ancient times and I am sure much experimentation was done to improve flavour and longevity, especially given the quality of water and food was not a guarantee.  We take for granted today our near universal access to clean drinking water in the modern western world, something that was not a given for brewers of old.

So I went online and through my history of brewing books and found all kinds of explanations as to how hops came to be used.  In the end I came back to an old faithful (though I don’t think the author, Martyn Cornell, would not appreciate the old bit), my favorite beer history blog, Zythophile.  In a post dated Nov 20th 2009 titled “A short history on hops” Mr Cornell provides a well researched and thorough piece on the hop and its rich history.  I will not try to re-write the piece, I could never do it justice and I would probably make a mistake, something Mr Cornell would get very upset with. He is not only a famous beer historian but a beer myth buster also and not afraid to speak out against inaccurate and lazy research. The one paragraph that leapt out of the page (or browser) was the following”

Book I, Chapter 61, “De Hoppho”, or “Concerning the hop”, says of the plant: “It is warm and dry, and has a moderate moisture, and is not very useful in benefiting man, because it makes melancholy grow in man and makes the soul of man sad, and weighs down his inner organs. But yet as a result of its own bitterness it keeps some putrefactions from drinks, to which it may be added, so that they may last so much longer.” (Abbess Hildegard of Bingen (1098-1179), mystical philosopher and healer, published a book called Physica Sacra, which translates best as “The Natural World” (circa 1150).

The author then goes on to note:

What probably kept the usefulness of hops from being discovered for so long is that the bittering, preserving resins in hop cones are not very soluble, and the hops need boiling for a long time, around 90 minutes, for what is called isomerisation

Please read the rest but the above brings us to the most important discussion around hops and brewing, how they work.  Male and female flowers form on separate hop plants. The hops used for brewing are the female flower cluster, which contains many small flowers.  Female hop flowers, also called cones, are harvested in August-September and dried.  The female cones are important because they contain lupulin glands that contain alpha and beta resins and other essential oils used to impart specific aroma and flavour characteristics.  Alpha and beta resins are measured as the % weight of the hop cone and displayed on the packaging as alpha acids and beta acids.

ALPHA ACIDS – contain the chemical agents Humulone, Cohumulone and Adhumulone and are used to impart bitterness, the higher the alpha % the more bitter the hop.  Alpha resins are not very soluble and require at least 60 mins boiling to extract the bitterness.

BETA ACIDS – Beta resins and hop oils are used to impart flavour and aroma.  Unlike the alpha acids these oils are water soluble and will quickly boil off in the kettle so cannot be in the pot for too long.  A hop will impart flavour if boiled between 5-15 mins and aroma if boiled for 1-3 mins.

An important note to brew calculator users.  The hop alpha and beta % used by these applications are averages for a particular variety.  The actual resin % does vary year to year and even crop to crop from the same region.  It is important to note the published %’s on a package prior to use and recalculate your recipe hop levels to ensure you maintain the appropriate bitterness and flavour characteristics.

A well designed and useful bitterness and flavour hop reference chart can be found here with another great reference on creating flavours found here. This chart and others like it can assist us when it comes to decide the type of hops we should use and the quantities and timing during the boil to attain the flavour and aroma characteristics for our final brew.  Experimenting with flavour is an art and something every homebrewer should have fun with. For example if I were to use the above chart to brew a great spicy, citrus American IPA consider the Williamette as your flavour and aroma hop.

While flavour and aroma are part of the art of homebrew, bitterness is more the science.  Bitterness is measured in most calculators and modern recipes in International Bittering Units (IBU’s).  There is debate as to the most accurate IBU formula for small batch homebrews but it appears that most books and online resources use the Tinseth formula created by hop head Glen Tinseth. Measured in parts per million (ppm), if you do not have access to a brewing calculator or just enjoy doing the brew math by hand here is the Tinseth formula for estimating a brews IBU:

IBU = Utilization * ( oz of hops * ( Alpha Acid% / 100 ) * 7490 ) / Gallons of Wort

Utilization refers to how much of the alpha acid is actually used and is dependent primarily on the boil time, but is also affected by specific gravity of the wort and whether the hops used are pellets or whole hops.  I will not use this post to get into a discussion on the use of pellets over whole leaf except to say I use pellets.  In my experience they are easier to store and stay fresh longer.  Typical utilization %’s are in the range of 15 to 25% depending on the length of the boil. Pelletized hops have about 10% more bittering potential than whole hops because the soft resins have been upset and made more available during the pelletizing process.   To calculate utilization using the Tinseth formula use the following (for pellet hops add 10% to the final value).

Utilization = ( 1.65 * 0.000125^( OG of the wort – 1 ) ) * ( ( 1 – 2.72^( -0.04 * Hop Boil Time ) ) / 4.14 )

Taking the Theakston Old Peculier brew I researched last week as an example with an IBU target of 29 and the research indicating the use of Fuggle hops. The Fuggle pellets I have in stock have a stated alpha of 4.5% so using the formula above, the alpha %, the batch size and target OG for the brew of 1.060 I would calculate the following:

Step 1 – calculate utilization for both the 60 mins and 15 min additi0ns (adding an additional 10% for pellets)

60 min: ( 1.65 * 0.000125^( 1.060 – 1 ) ) * ( ( 1 – 2.72^( -0.04 * 60 ) ) / 4.14 ) = 21.14% (whole hops) or 23.25% (pellet hops)

15 min: ( 1.65 * 0.000125^( 1.060 – 1 ) ) * ( ( 1 – 2.72^( -0.04 * 15 ) ) / 4.14 ) = 10.5% (whole hops) or 11.5% (pellet hops)

Step 2 – calculate the IBU for the final brew, you may need to

play around with the hop quantities to get the final IBU right. Remember that higher quantities of later addition hops lead to a more intense the flavour and aroma without adding to the bitterness.

60 min: 23.25 * ( 0.67 * ( 4.5 / 100 ) * 7490 ) / 2.5 = 21

15 min: 11.5 * ( 0.53 * ( 4.5 / 100 ) * 7490 ) / 2.5 = 8.25

IBU = 29.25 (21 + 8.25)

Hope this has helped. I have included a basic excel spreadsheet with the above example.  Have fun, remember to always check the alpha % and adjust your recipe accordingly, research recipes from your favorite brews to see the types of hops used and investigate the websites of your favorite commercial brews as they often post the hops they use and associated tasting notes. Next up the Malt and yes there will be more math.

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  • CraigHesse

    Hi Stephen, not really sure how I originally happened upon your blog but am very pleased that I did.
    Thank you, I have over the weeks read just about everything you have posted. I was in Wales in 2006 where I was gratefully exposed to Old Speckled Hen and have craved it ever since. I am brewing my first batch of Irish Stout that came as a kit when I ordered my brewing equipment. I am going to bottle it this weekend.
    I have received my order of ingredients for two 5 gallon batches of Old Speckled lacking Challenger hops. I located them in a local supply store but your clone version calls for AA9.6 pellets. The Challenger hops I purchased are AA5.5. The man did a quick mental calculation and said I needed to use 1.46 oz. for bittering instead of .917 oz. as your recipe calls for. He also said to use .46 oz. for flavor instead of .25.
    Do these figures sound correct to you?
    If so how did he manage to make that calculation so quickly without a calculator so that I may do that my self?
    I would like to start my Old Speckled on Sunday but am hesitant about the correct amount of hops.
    Hope you have a quick response. Thanks for everything I’ve read!

  • Stephen C Jenvey

    Craig, thanks for reading. This recipe is indeed one of my favorites. Please make sure you followed this recipe.

    I also use the beer calculus tool on the Hopville site to help balance the bittering and flavor hops with the fermentables.

    I would try by adding the ingredients to the Hopville calculator and changing the AA % to 5.5 and see what happens to the IBU. I also have a spreadsheet on my hops post that walks you through the calculation used by BeerCalculus.

    I did do a quick calculation and would estimate that 1.5 oz of bittering and 0.25oz of flavor for 15mins will get you close.

    Have fun and let me know how it goes.

  • CraigHesse

     Thanks again Stephen. I’m going to use 9 oz. of Belgian soft candi sugar (brown) in place of cane sugar. Mostly because I like brown sugar but also because of the color. I’m starting Old Speckled this afternoon. Just to confirm, the sugar is for priming and bottling isn’t that correct? It does not go into the original boil.

  • Stephen C Jenvey

    Actually the sugar is added at the end of the fermentation to boost the SG.  Its a common trick used by many traditional British Breweries.  I cover this in the post on the recipe.  The idea being you get a stronger drink without effecting the flavor balance.  Have fun and let me know how it turns out.

  • Craighesse

     You are ever so helpful Stephen. Thanks.
    The Irish Stout I made did not last very long. Too many others enjoyed it too much! It was a kit recipe from Midwestern.
    I have finished and bottled my Old Speckled according to your info. This coming Saturday will make it 2 full weeks. I learned from the stout not to rush the tasting. After 2 weeks it was not to my liking much. However after 4-5 weeks it was darn good!
    So I have no plans to even think about the Old Speckled until about 5 weeks. Currently it is pretty cloudy and I’m hoping that will clear considerably at 55 degrees. I have however run into a snag. Prior to Hopville’s upgrade on the beer calculus your figures jived with the calculus and you recipe. Now however, they do not. The specific gravity is way off as well as the IBU and ABV. Any comments on that?

  • Craighesse

     Stephen, I just looked at this link again ( I do that frequently) and it has
    changed dramatically!  What gives?

  • Stephen C Jenvey

    I have no idea. It would appear the Hopville creator is making a number of changes to his site. I cannot even access the recipe at this time.

  • Stephen C Jenvey

    Its really hard to say. I verified the recipe with the alpha acid % you gave. All I can suggest is to try again once whenever Todd at Hopville completes the upgrades he is doing on his site. As I mentioned in a prior post I cannot even link to my recipes right now.

  • Stephen C Jenvey

    Craig, I just tried again on Hopville. I managed to find my recipes.  It would appear hopville has changed their formulas and added some new features which is breaking both the process description in Hopville and the recipe formulas. I would not worry. As long as your OG and FG were in line with my original recipe at the time of brewing AND the batch clears and carbonates the beer will be excellent.

  • Craighesse

    Thanks for replying Stephen.

    I must admit I’m not real concerned about the clarity but more concerned with the TASTE. If it is even close it will save me $12.50 a six pack!

     I attended a beer recipe class this past Tuesday. It was educational and I learned more than I did at the brewing class I attended a few weeks earlier. I was informed about a program for Macintosh called Beer Tools They have a free trial period and the program is about $27. Thought I would give it a trial and see what your figures produce on that.
    I did use your recipe for the clone not the original version.
    On Hopville your IBU used to be 30.1, now with the beta version it is 46+.
    Wonder what happened.

  • Martin Ujházi

    Hello, nice blog.
    I am trying to brew from fresh ingredients, so I bought some hops plants from england:) I like taste of english ales, but i have no skills with English beer brewing. So I will have tons of english hop and iam looking for some recieps.

    I have these plants:

    Northern Brewer
    Brambling Cross

    I heard that WGV is similar to Goldings, which you are using often. Maybe I could use Target or Pheonix instead Challenger..

    Any ideas how to combine these hop, in what ration?:)

    Greetings from Slovakia

  • Stephen C Jenvey

    great list of hops. The list of beers you could brew is endless with this combination. I would recommend using and search for recipes with the hops you have listed.
    WGV is both a great bittering and aroma hop and can be used in American and English Pales. Its also a good replacement for Goldings. It actually is a Golding variety. Target is a good replacement for Challenger but check the % IBU matches. I got burned once where the two were very different leading to an overly bitter batch.
    Have fun most of all.

  • Áron Varga


    At two Tinseth formulas you calculated with the same gallons (2,5) of wort, but it is changing during the boiling because of evaporating. Other formulas calculated with brew length. Which is right? Calculate with (actual) amount of wort or brew length?


  • Stephen C Jenvey

    Both are right, I guess its what makes sense for you. Brew time effects the amount of bitterness extracted the amount of wort would effect the overall flavor. The spreadsheet provided as a link is the one I use most often.