Drunken Speculation

WTF is a Lupulin Shift?

A lupulin shift, or more formally, a lupulin threshold shift, is something that I mention from time to time. My review of Sierra Nevada Pale Ale was tainted by Bridge Road’s Hop Harvest Ale and my hypothesis is that lupulin shifts are responsible for the popularity of IPA.

Vinnie Cilurzo, brewer at the famous Russian River Brewing Company, coined the term, which was popularised in part by Stan Hieronymous. It is, in short, summarised by this simple graphic:

lupulin shift

I tend to use it in the sense that one’s palate becomes acclimatised to hoppiness and bitterness. Beers that once impressed with their flavour, bitterness and hoppy aroma don’t seem as interesting when you’ve been exposed to beers with more intense flavour, stronger bitterness and an overwhelming potpourri of aroma. It’s a phenomenon that interests me, so I’m going to explore a little deeper.

The pursuit of hoppiness

Hop flowers are remarkable. Once upon a time, beer wasn’t hopped. Instead, medieval brewers would use a mix of spices, nettles, flowers and other herbs to give beer some flavour (refer gruit). Around the thirteenth century, the inclusion of the female flower of Humulus lupulus in brewing beer began to become commonplace because it improved the the beer’s head retention and its shelf life. Boiled hops also release alpha acids, primarily a chemical called humulone, which gives modern beer its characteristic bitterness.

It’s now rare to find a beer without hops. A well hopped beer will tickle your in-built fancy for flowers, fruits and other sweet smelling greenery. Your ability to taste bitterness evolved as a way of detecting poison. It’s then interesting that we have developed an acquired taste for bitter food and drink that seems rare elsewhere in nature. Perhaps it’s this contrast that makes a good pale ale, IPA or imperial IPA so appealing?

512px-(S)-HumuloneMeasuring bitterness

IBU is the International Bitterness Unit, a quantitative measure of bitterness. Bittering units are measured through the use of a spectrophotometer, solvent extraction and other scientific, brewing wizardry.

Beers designed in computer software will calculate a theoretical IBU level which, for particularly highly hopped beers, rarely meets the measured IBUs because chemistry*. Mikkeller’s 1000 IBU beer, for example, probably packs 1000 IBU worth of hops but, according to Ross Kenrick of Bacchus Brewing, it likely sits around 110-120 in practice.

The shift

That we get used to things, or to build up a tolerance, is central to the human experience, albeit one not considered consciously until you’ve gone to a party, finished a bottle and a half of vodka without getting a buzz. You then realise you’ve developed a “tolerance” (and also a problem).

It’s no surprise then that people, beer geeks in particular, are capable of building up a tolerance to hoppiness and bitterness. For beer enthusiasts, there is more buzz around hoppy beers than is probably healthy and the push for ever increasing metrics – IBU, ABV, Untappd checkins – means that as your beer journey progresses, your palate is likely to be challenged with increasingly powerful flavours, causing you to undergo a lupulin threshold shift.

Lupulin thresholds

My hypothesis is that these threshhold shifts come in bands of around 30-40 IBU. Once you step up a band, your palate becomes jaded at the new level and you find it difficult to get the same euphoric rush that the beers below once brought. Indeed, going down a band requires a great deal more concentration to identify hop character and bitterness.

Observe, doesn’t the following look remarkably similar to entry level beers, craft beer and proper beer geekitude?

ipa glassware i

Personally, I see myself at L.3, which is less a badge of honour and more a way for you to calibrate your palate to mine when I talk about bitterness. Nonetheless, parallels between these thresholds and Achieving Beer Nirvana wouldn’t be far off the mark. Perhaps it’s another way of tracking your beer journey that doesn’t result in you spending an allegorical eternity in an allegorical flaming tomb. Then again, if you want a charity-based excuse to try for L.HC, maybe try Hair of the Blog – The Second Combing & World’s Greatest Shave.

For the readers, what threshold are you finding yourself drinking at?

*I will find out why this is one day. I suspect that the boil delivers diminishing hoppy returns because there is proportionally less water to scrub the hop surface area of its acids.


  1. LifeandTimesofCB

    Big fan of these educational posts guys – not that all your other posts aren’t “educational” off course.

  2. I find the LTS isn’t set in stone. If you steer clear of hoppy beers for even a week or so, your approach to hops can change.
    Also, I’m keenly aware that, if I taste a beer I used to like but find it lacking, then it’s most likely me who has changed and not the beer. I’m not one of those guys who will claim the brewer has dumbed down the recipe when it’s my taste buds that have changed.

    • True that about the LTS shifting, although I think its mentally easier to go back to L.3 (for example) once you’ve been there than breaking through for the first time.

  3. Pingback: Homebrew Wednesday 48: A step towards the “Lupulin Threshold Shift” | The Brewed Palate

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