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Silly hop whirlpool question

Discussion in 'General Brewing Techniques' started by theredone, 15/8/19.

 

  1. theredone

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    Posted 15/8/19
    sorry probably silly question, if I’m doing a massive hop bomb with both big 5 min additions and whirlpool(chill to 80 add and leave for 30) additions I’m assuming the 5 min additions will also contribute throughout the whirlpool as well right? As in the 5 min addition might contribute 20 ibus on calculators but u need to account for that hop remaining in the whirlpool as well contributing addition ibu? Basically as if u would have added them again contributing another 5-10 ibu maybe? Probably not explaining that well but hopefully someone is following my thought train?
     
  2. hairydog

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    Posted 15/8/19
    IBU calculations have to allow for whirlpool time on total of hops,more importantly the late hop additions.The hops added at 80 deg will strip less alpha acid than the boil, its very hard to measure
    you can only calculate and adjust in future brews to your taste.
     
  3. Schikitar

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    Posted 16/8/19
    If you are going for whirlpool steeping and trying to avoid adding too many IBUs then just chill to ~75 degrees (not 80) to be in that safer window. That way your 5 min addition calc will be pretty right and will all but cease contributing IBUs once you get down to 75. Personally, I chill to 65 and whirlpool at that temp for 20-30 mins. Just remember though, any hop addition will change the perceived bitterness regardless of temp - have you ever made a hop tea at sub 80 temps and had a sip, quite intense!
     
  4. theredone

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    Posted 17/8/19
    ah cool, thanks for the responses
     
  5. MHB

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    Posted 17/8/19
    It isn't a silly question, just incredibly complicated, personally I think its a very good question.
    There is little definitive research done on the amount of bitterness added by late hop additions. Most of the brewing research is funded by big breweries and by the nature of what they make it isn't really an area that is of much interest to them.

    The first problem is that a lot of beer tasters (include Brewers) cant tell the difference between Bitterness (defined as mg/L of Isomerised Alpha Acids) and hop taste.
    Hops can add three main components to beer Bitterness, Hop Taste (or sensation) and Hop Aroma.
    Aromatic compounds by their nature become volatile (that's why we can smell them) the more heat and time hot they are exposed to the less will be in the beer (makes the boil smell great but not the beer). So to get the most hop aroma we add hops late.
    Hop taste is flavour compounds that are extracted from hops, there are hundreds of them. They will given time in the boil break down or boil off. There is a lot of argument as to the best time to add hops for flavour, there is measurably more from 20 minutes in the kettle, arguably we get a smoother more pleasant flavour from additions at around 10 minutes from the end of the boil. Cant say other than that there are so many compounds with different properties involved that its going to depend on what you want from a given hop in ang style of beer, really only something that you can determine by experimenting and the difference between a 10 and 20 minute addition can be pretty big, so lots of opportunity for fine tuning a recipe. I suspect it takes some time for all the flavour compounds into solution (will depend on which particular flavor components we are look in at) and the temperature will affect both the time it takes and the amount you get. Try making 3 cups of tea with a teabag each, at say 60-80-100oC all will taste and smell very different.
    Bitterness, this is where it gets really interesting (complex). Hops contain a group of three related compounds called Alpha Acids, AA is pretty much insoluble, boil AA long enough and some of it will get rearranged (same atoms just hooked up differently is called an Isomer), the isomers of AA now called Iso-Alpha Acids are somewhat soluble. but they are also a bit unstable so if you boil long enough they will break down into Trans Iso-Alpha Degradation Products. {Slightly off topic but these aren't very bitter, but have a very mellow flavour and add a unique character usually only observed in very big (high OG) beers that have been boiled for a long time (+3 hours) like some barley wines, Imperial whatever...).
    Part of the problem is that both processes are going on at any temperature both happen faster as the temperature goes up (see the equation in the paper attached) but isomerisation is always happening. From the equations for Isomerisation kinetics the rate at which this happens at a given temperature would look like this.
    upload_2019-8-17_11-57-19.png
    As you can see, under 60oC the rate is very slow (negatable) but from say 80oC on it happens much faster, fast enough to have a real impact on your finished IBU'.
    You might get a rough idea of the relative effect by abstracting from the rate/temperature as compared to what will happen at 100oC.
    Mark
     

    Attached Files:

  6. gaijin

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    Posted 17/8/19
    To give you a guide, my whirlpool hops are dropped in the moment I turn the gas off and run the cooling coil. I've worked out they contribute 5mins worth of IBUs to my wort as if I had added a 'standard' 5min addition. This is because they're contributing IBUs until the temperature drops below 80. In a 40L batch, 200g of 10-15%AA hops gives me 20-30IBUs.

    For NEIPAs, I generally add 10-20IBUs (10-20g) of first wort hops to give a smooth bitter backbone, with all other IBUs from whirlpool hops. Works amazingly.

    Hope this helps with your recipes.
     
    Last edited: 17/8/19
    theredone and razz like this.
  7. Mash_Hound

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    Posted 18/8/19
    What is Twitter?
     

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