# No Chill IPA - Staggered IBU



## Lord Raja Goomba I (27/12/16)

Finally got around to brewing my house AIPA, which is SWMBO favourite.

Trouble is, as I've mentioned on other topics, I don't reckon the 'hoppiness' qualitative factor is quite there, but the bitterness seems to be higher (perceived, I know) than is typical for this recipe (which is very much unchanged for several years). In Tassie, I had this same recipe feel less bitter and more hoppy punchy type flavour.

My very non-measured opinion is that the temp difference between here and Tassie means that no-chill stays above isomerisation temps longer in Qld due to the slower temp decline (or less gap between the wort temp and outside temp). This seems to be further reinforced by the fact that I could leave a no-chill cube overnight in Tassie and it would be at pitching temp in a shorter period of time (say "it was ready when I got out of bed", rather than midday or 1pm here).

So I decided to do a semi-scientific, semi-dark ages experiment. Given that 'hoppiness' in no-chilled IPA tends to be a very qualitative thing and we have educated guesses as to what the extra time gives us over chilled beers, this is probably in keeping with the slightly non-scientific manner of measuring no-chill variables at any rate.

It's basically a case of whacking the hops into the cube after a period of time has elapsed, to reduced the bitterness and increase the qualitative hop factors of IPA (aroma, flavour), so that the (generally anecdotally assigned) +20 minutes that no-chill adds to a hopping regime, can be adjusted down to +15 minutes or even possibly +ten.

So, assuming that the wort goes in at boiling (100 degrees C), and isomerisation is generally considered, from my reading to be around 79 degrees, I wanted to aim at 95 degree pitch.

Now, I know that cooling does not happen in a straight line, but in the absence of any research I've found that gives a calculation to get a 'line in the sand' moment, this is the best I can do.

So given that 95 degrees is 5 degrees of 21 degrees from 100 degrees to 79 (isomerisation ceases from literature reading), I back calculated the IBU to be a no-chill 70 IBU, which, using the formulate (isomerisation range - drop in temp) / isomerisation range * IBU, I calculate this to be 53 IBU. Ideal.

All other variables (hop variety, base malt, recipe, yeast) are the same. I want to see if I get more qualitative 'aroma' and 'flavour' that we normally associate with 'hoppiness'.

If this works (or the result is in the ballpark of where I think it might be), I can then hone a method (much like the housewives of 1660) that allows me to produce a fairly replicable and predictable result with hopping IPA using no chill but staggering the hop additions.

I'm also timing how long it takes to drop 5 degrees and I'll see if this needs to be tweaked depending on outside temp/season.

This is no brulosophy. It may give me a false positive, though I have a very harsh critic. It's only the stuff I can measure reasonably predictably not the 'whole picture'. But it will hopefully give me an idea of where to go.


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## Lyrebird_Cycles (27/12/16)

I have the calculation required for the "line in the sand" incorporated into my bitterness calculator. All you need is the temperature when the hops go in and the time taken to a suitable end point such as 50 degrees. It assumes that heat loss follows a log curve between these two points as dE/dt = k * deltaT

BTW isomerisation doesn't magically stop at a particular temperature, it has a typical first order Arrhenius kinetic curve.


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## Lord Raja Goomba I (27/12/16)

I figured that there might be a calc and that it wouldn't be a straight line thing.

This gives me a starting point in a numbers game. 

I'll incorporate that into the next attempt as I fine tune it.

Thanks heaps


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## Phoney (27/12/16)

Lyrebird_Cycles said:


> I have the calculation required for the "line in the sand" incorporated into my bitterness calculator. All you need is the temperature when the hops go in and the time taken to a suitable end point such as 50 degrees. It assumes that heat loss follows a log curve between these two points as dE/dt = k * deltaT


Whaoh whaoh whaoh! Slow down egg head, what's dE, k and the rest of it?


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## Lyrebird_Cycles (27/12/16)

"dE/dt" is the rate of flux of energy (in this case heat) with time*. "k" is a rate constant. "DeltaT" is the temperature difference between the two fluids (in this case one fluid is air). I have glossed over the surface factors and just assumed they are constant so they get rolled into k.

In engineering calulations it's normal to use Q for heat transfer rate but I thought that would be even more obscure.


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## Lyrebird_Cycles (27/12/16)

Lord Raja Goomba I said:


> I'll incorporate that into the next attempt as I fine tune it.


The reason for the usual end point number given somewhere around 80 oC is that it's the point at which the isomerisation rate falls to 1% of its value at 100 oC.

It is usual practice when considering reaction rates in biochemistry to assume that, all things being equal, once the rate falls to 1% of its peak value leaving the rest out won't cause significant errors.

In the case of no chill, the "all things being equal" doesn't apply because you are comparing boil times in minutes with cooling times in hours: if the wort spent 24 hours at the temperature where the isomerisation rate was 1% of boiling, that would contribute the equivalent of almost 15 minutes of boil time.


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## manticle (27/12/16)

Sure but how would wort remain at that temp for anything close to 24 hours?


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## Lyrebird_Cycles (27/12/16)

It's just an example of a situation where applying the idea of a cutoff temperature introduces a quantifiable error.


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## manticle (27/12/16)

Fair enough.


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## Coodgee (27/12/16)

Lyrebird_Cycles said:


> I have the calculation required for the "line in the sand" incorporated into my bitterness calculator. All you need is the temperature when the hops go in and the time taken to a suitable end point such as 50 degrees. It assumes that heat loss follows a log curve between these two points as dE/dt = k * deltaT
> 
> BTW isomerisation doesn't magically stop at a particular temperature, it has a typical first order Arrhenius kinetic curve.


Not sure if trying to be helpful or seeking to show how smart you are.


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## Lord Raja Goomba I (27/12/16)

Lyrebird_Cycles said:


> The reason for the usual end point number given somewhere around 80 oC is that it's the point at which the isomerisation rate falls to 1% of its value at 100 oC.
> 
> It is usual practice when considering reaction rates in biochemistry to assume that, all things being equal, once the rate falls to 1% of its peak value leaving the rest out won't cause significant errors.
> 
> In the case of no chill, the "all things being equal" doesn't apply because you are comparing boil times in minutes with cooling times in hours: if the wort spent 24 hours at the temperature where the isomerisation rate was 1% of boiling, that would contribute the equivalent of almost 15 minutes of boil time.


That makes so much more sense viz no chill.


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## malt junkie (27/12/16)

LRG .... just tell the missus " with all these kids and summers getting hotter, we need a pool babe, ..... " she'll go for it for sure!


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## manticle (27/12/16)

Coodgee said:


> Not sure if trying to be helpful or seeking to show how smart you are.


LC developed a bitterness calculator which he shared free with the forum some time ago so my guess is the former.

This forum is at its best when it has a balance of various level members, including those with high level maths and science pertinent to brewing.

I'd rather arrhenius than LCD.


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## wereprawn (27/12/16)

Coodgee said:


> Not sure if trying to be helpful or seeking to show how smart you are.


Meh, having a chemistry wiz on the forum is a good thing. I often have not the slightest idea of what LC is talking about, but when I do I find his posts informative.


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## Reedy (27/12/16)

Very interested to see the results of your exbeeriment LRG


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## stewy (28/12/16)

Before I started throwing my cubes into the pool I would wait approx 30 mins after boil (crow urn, uninsulated), have all of my late hop additions in the cube & transfer the wort at that stage. Wort temp was generally around 85C at that point. It resulted in nice hop punch without excess bitterness. Another option for you is to transfer straight away, leave 20 mins in cube then put into a full bath (or pool if you have)... this works exceptionally well for me.


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## Reedy (28/12/16)

stewy said:


> Before I started throwing my cubes into the pool I would wait approx 30 mins after boil (crow urn, uninsulated), have all of my late hop additions in the cube & transfer the wort at that stage. Wort temp was generally around 85C at that point. It resulted in nice hop punch without excess bitterness. Another option for you is to transfer straight away, leave 20 mins in cube then put into a full bath (or pool if you have)... this works exceptionally well for me.


What do you consider late hop additions? Anything 20mins or less? I ask as I am still trying to 'perfect' my no chill technique for IPA's, and cube hopping is something I want to try.


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## stewy (29/12/16)

Yep, 20 or less. Although I do IPA's with first addition at 20mins, a load at flameout, another load cube hopped. Come out much better. Huge aroma, nice smooth bitterness. 
After boil finishes I let it sit 10mins, drain to cube & leave in cube for 20. I then chuck in pool. Works a treat. You could chuck in bath full of cold water. Don't need it to get to pitching temps, just knock as much off as quickly as possible to lock in the hop flavour/aroma


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## stewy (29/12/16)

.


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## Rocker1986 (29/12/16)

I would have thought it was pretty standard practice with no chill brewing to let the wort sit in the kettle for 15 minutes or more before transferring it to the cube to allow the hot break to settle out in the bottom of the kettle first. If it's transferred basically immediately after flameout, most of that shit would still be floating around in the wort and end up in the cube, wouldn't it? :unsure:

I let mine sit 20 minutes before transferring now. I did test the temperature of the wort in the urn at transfer time once, which I think was after a 15 min stand, and unfortunately no idea what time of year it was now, but it was sitting at 92C by that stage. I imagine it would have lost a little more during the transfer into the cooler cube as well. Next brew day I'll have to test it after its 20 minute stand and also when the cube is ready to be sealed up. Would be interesting to see what the temps are.


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## manticle (29/12/16)

Mine sits for 20, whirlpool (with any late additions) then sit another 20 before transfer.

Heat loss will vary depending on actual volume and amient temps but have previously measured 80+ going into cube.

I leave the lid on during this although it's a keggle and the keg handles allow heat and vapour escape while the lid resists dust/leaves, etc.


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## Lyrebird_Cycles (29/12/16)

manticle said:


> I leave the lid on during this although it's a keggle and the keg handles allow heat and vapour escape while the lid resists dust/leaves, etc.


I think you'd be surprised at how little of the cooling is from evaporation: to cool the wort by 5 degrees C you'd need to flash off 1% of the volume, which doesn't happen.


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## manticle (29/12/16)

Leaving for 40 odd mins and having fairly small heat loss means I'm not especially surprised. My understanding, although much more layman like, is that unless actively agitating and/or encouraging a more efficient form of heat exchange, that volume of hot liquid will hold its thermal mass pretty well.

Mostly vapour escape for me at that point is the last exit route for volatiles although it's merely from structure of my kettle and available lid than anything deliberate.


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## manticle (29/12/16)

Sitting in a surgery waiting room typing on a phone - I realise last post may not make sense.


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## Rocker1986 (29/12/16)

I put the lid over the top of my urn at flameout as well, with the hop spider in there it sits above it by about 20-30mm, so not completely closed off. It's more for stopping shit dropping into it than anything else. It stays on there until the urn is just about emptied, when it is taken off so I can see the hot break begin to move towards the tap outlet.


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## rude (29/12/16)

MMM I transfer straight away into cube

Could you pour carefully & leave hot break in the cube would it settle at the bottom ?

I also leave in cube for 20 mins then into the pool


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## manticle (29/12/16)

It will settle although pouring brings clumps back into solution.


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## Rocker1986 (29/12/16)

It does settle but I find as soon as the cube is moved it stirs it up again, hence why I avoid getting it in there in the first place.


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## Fatgodzilla (1/1/17)

Enjoying this thread, even if it is going slightly off track. No idea what LC is talking but it's great to see knowledge and passion mix.
I turn off my Birko 40l and simply leave for half an hour. Don't whirlpool. The wort settles nicely and into cube fairly clear. My problem is what I think the thread started as .. Hop bitterness and no chill. I haven't made a decent high IBU brew as I get excessive bitterness without the flavour, so really would like someone to give me a simple hopping schedule for someone who biabs, no chills and doesn't own a pool or a bathtub. Appreciate that the cubes will cool at different rates depending on the air temperaure. Did I read somewhere someone has had a go at it?


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## manticle (1/1/17)

What methods have you tried fatz?

I add all my flavour hops for hoppier brews to whirlpool so adding yours just prior to draining to cube would be similar.

Otherwise cube hop or argon method?

If none of those work, chill.


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## Lord Raja Goomba I (1/1/17)

Yup, the point of the thread was to get an idea of how waiting for the wort to cool a little and see what effect it has on bittering vs aroma. 

I had less a problem in Tas, but traditionally before then, had chilled all hoppy beers. Given that involved sticking pots in the sink and rolling cool (or lukewarm in a Qld summer) water around the outside of the pot, I would really like a method that would give the hoppiness, bitterness and the balance needed, but all be replicable.

Update: It's going into chill, from what it tastes out of the fermenter, balanced, a bit more hoppy, but balanced. The IBU was about 70 calculated ,and tastes pretty much around the 50 IBU mark. Once it's been carbonated in the keg, I'll get a better feel. But so far, looking promising.

Next attempt at this, will be more calculated using the formulae that LC has provided to tweak this.


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## Fatgodzilla (2/1/17)

manticle said:


> What methods have you tried fatz?
> I add all my flavour hops for hoppier brews to whirlpool so adding yours just prior to draining to cube would be similar.
> Otherwise cube hop or argon method?
> If none of those work, chill.


I guess the biggest problem has to be the time the hops are in contact with the wort. I've never been much of a scientist, I'm more arsehole than anal. But I appreciate all hopping rates in all popular recipes are based on chilling the wort asap. 

I've thinking about this all night (at my age dreaming/thinking beer is all I got) and have got to re-establish some simple brewing principles. Please confirm or correct in relation to bitterness and flavour.

1. The temperature of the wort is the principal factor that will affect oil extraction from hops 
2. Once the hops are separated from the wort, what has been extracted from the hops will no longer change

Or to bring this back to LRG's original concept, will the slow cooling of a cube continue to affect whatever hop oils etc. has been extracted?


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## contrarian (2/1/17)

I would think that temperature is important but there would be elements of boiling wort that would also have an impact so that changes in volatiles in boiling wort would be slightly different to wort at say 90C. 

I would also speculate that the change of volatiles into bitterness compound would happen more quickly at boiling than at 80C. 

I had trouble for a long time getting a flavour and aroma I was happy with from no chill but have finally made one I like and it had 50% of calculated IBUs at 60 and the rest added into the whirlpool at around 85-90C and that seemed to work. 

I have also made pale ales that were 100% cube hopped that turned out well. 

It really is guess work calculating IBUs with those kinds of additions as most calculators attribute no IBUs to 0 minute additions. 

I would also suggest that even chillers have big variations in what they do after flame out that impact how long wort would be above utilization temperatures. 

It really is trial and error on any individual system to get results you like.


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## Fatgodzilla (2/1/17)

contrarian said:


> It really is trial and error on any individual system to get results you like.



Correct fella (and Happy New Year).

But what I hope LRG might eventually lead us fellow wanderers in the desert is a SIMPLE (read general rule of thumb) scale of measuring (roughly/approximately) the effect of hop isomerisation over the time it takes a cube to cool to pitching temperature. That Lyrebird bloke looks to have a key that will give him something to work with. LRG was thinking about a system based experiment, now he may be able to make shortcuts in the process.

Go man go.

But it is the results that's important, but its got to be made simple. I'm really the world's laziest brewer so don't want to have to overthink anything. I like plugging recipes into (say) Beersmith and making that brew. However, we "hot" cubists (brewers without swimming pools) have simply made 15-20 minute adjustments on hop additions and hoped for the best. Wouldn't it be good if we can use a better ibu / flavour determination based on something other than trial and error?

If work on no-chill and hop isomerisation can lead to some better knowledge that will lead to positive results (which in this case was a desire for repeatability of a recipe), then the world will be a better place.

I'm going to brew an IPA today rather than go to the Narooma Cup race meeting (the things I do for brewing, plus the weather looks dodgy) using the advice of Manticle and Contrarian and hope for a good brew (or at least something good enough to go into the next IBU case swap .. and I'll make a stout tomorrow as insurance). I will measure temperature at all levels of the production into the cube for the first time ever.

And think about brewing ............ :super:


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## contrarian (2/1/17)

Happy new year! 

A rule of thumb that worked would be great but I doubt there will be any great degree of accuracy without things getting fairly complicated. For starters, when describing recipes Brewers would need to be much more specific about their post flame out process in terms of time, temperature etc. 

Hope the IPA comes out well!


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## manticle (2/1/17)

As a very general rule of thumb Fatz:

1. Bitter alpha acids get dissolved into the wort when it's hot. Most activity happens above 80 deg with hotter wort increasing that rate.

2. Hop bitterness can increase even if the visible hop material has been removed ( say in a hop sock for example).

3. Hop chemistry is complex but you can still keep it simple.

4. Good luck. Brew on.


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## Fatgodzilla (2/1/17)

Thanks Manticle, but please don't call me Batz. I'm way better looking than him. And I'm not a Queenslander -_-


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## manticle (2/1/17)

Typo from my bat fingers on a vone


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## Lyrebird_Cycles (2/1/17)

Fatgodzilla said:


> 1. The temperature of the wort is the principal factor that will affect oil extraction from hops
> 2. Once the hops are separated from the wort, what has been extracted from the hops will no longer change
> 
> (3)* will the slow cooling of a cube continue to affect whatever hop oils etc. has been extracted?
> ...


1. Yes and no: it's complicated.

2. Not so: it will continue to change

3. Yes

There are five* things going on simultaneously: extraction of alpha acids, isomerisation of the alpha acids to the bitter iso alpha acids (IAA), degradation of the iso alpha acids to less bitter compounds, extraction of flavour compounds other than alpha acids and volatilisation (loss) of these flavour compounds.

The two extraction steps (1 and 4 above) are both included in extraction from hops. I do not know of any studies that give accurate estimates of the extraction rates involved, presumably because they are highly variable with things like lupulin gland size and structure, degree of rupture during processing and the activity of contact surfaces. If you've ever rubbed a fresh hop in your hand you'll know that the resins are released quite quickly and that they stick to everything.

Two further complications arise: the resinous material (AKA hop oils) can be released into the wort without dissolving (sometimes it's visible as oily spots) and since all hop components are poorly soluble but IAAs are more soluble than AAs, some of step 1 occurs after step 2 eg the alpha acids are isomerised in situ then the IAAs formed dissolve into the wort. This effect is exploited in pre-isomerised hop pellets.

All of these processes are influenced by temperature but only the temperature effect on steps 2 and 3 are well characterised. The extraction rates are also influenced by the boil vigour, stirring (if present) and such things as passage through a calandria.

It follows from the above that wort drawn from the kettle will have alpha acids that aren't yet isomerised entrained in it and further exposure to heat will transform these to IAAs, increasing the bitterness. This includes slow cooling time in the cube.


* Actually there are lots of other things going on at once but these are the five that concern us here.


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## Fatgodzilla (2/1/17)

Even I understood (most of that). This last bit


> It follows from the above that wort drawn from the kettle will have alpha acids that aren't yet isomerised entrained in it and further heating will transform these to IAAs, increasing the bitterness, including slow cooling time in the cube



Any idea of how much this might be? I know its a piece of string question, but talking about the big hops used in larger quantities and late hopping, such as in hoppy pales and IPAs (rather than the low volume for darker porters, stouts etc). So are we talking about, after say whirlpool waiting ( say 1/2 hour after active boiling has stopped) large enough quantities of these alpha acids in solution that the slow cooling process will continue to work on, or are the amounts small (or small enough not to have a realistic effect).


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## contrarian (2/1/17)

So under around 80C does the isomerisation become negligible or is it more of a factor of time at a specific temperature?


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## Lyrebird_Cycles (2/1/17)

Both of these are covered in posts #2, #5 and #6 above.


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## contrarian (2/1/17)

Ok, have re read those posts and that seems to make sense to me. Not sure I understand the formula but the general principle I get.


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