Hop isomerization after flame-out

[amarks6]

Apologies if this is a stupid question.

From what I can gather, apart from "no-chillers", some brewers chill wort relatively quickly by recycling it through a counter-flow chiller back into the kettle or by using an immersion chiller.

Others (like me) allow the boiled wort to settle in the kettle for up to 20-30 minutes after flame-out, before running it through a plate chiller in one pass into the fermenter.

It seems to me that holding the wort at high temps for an extra 20 minutes or so should extract more bitterness from late addition hops.

Does anyone adjust the timing of late hop additions when designing recipes around a delayed chill?

 

[Lyrebird_Cycles]

I don't adjust the timing (that's done on flavour) but I do adjust the bitterness to take account of the degree of isomerisation as the wort cools. I assume a logarithmic cooling curve and cut off at 50 oC, seems to work out.

 

[Killer Brew]

I try to get mine cooling asap for this reason. If i couldn't then timing adjustment of late hops would be the option I would go for. Its a bigger challenge at the commercial level given the volume of wort needing to be cooled meaning long contact time with very hot wort for late hops in the kettle. Whirlpool hopping, hop backs or even just waiting until a certain amount of the wort has exited to the heat exchanger before adding late additions to the kettle are all methods used to get around this.

 

[amarks6]

I don't adjust the timing (that's done on flavour) but I do adjust the bitterness to take account of the degree of isomerisation as the wort cools. I assume a logarithmic cooling curve and cut off at 50 oC, seems to work out.

Thanks.

So you reduce quantities of late addition hops?

 

[Killer Brew]

I think he is talking to making adjustment to to his initial bittering addition (reduced) to take into account the extended contact time and hence isomerisation of his late additions.

 

[Lyrebird_Cycles]

No, late hops are for flavour.

To adjust bitterness I'll tweak the kettle hops. I usually use a combination of two hops in the kettle, one with higher alpha than the other*. If I want to tweak bitterness by a unit or two I'll change their relative proportions to suit.

Edit: Yes to Killer Brew


* but both low by modern standards, I don't like the bitterness I get from the new triploid and tetraploid hop varieties.

 

[Killer Brew]

To answer your original question and if you are doing a 60 min boil followed by a 30 min kettle stand then:
- for bittering either enter it as a 90 min addition if added at start of boil or add them at 30 min to give you a 60 min total addition (both would need some assumptive work on volume adjustment given utilisation in the last 30 min would be somewhat less than full boil).
- for flavouring and aroma I would adjust the timing of these late additions to achieve the level of contact you are looking for (ie. what would normally be a 10 min addition may actually be added 20 min after flameout).

Perhaps do a search on hopstands and also on no chill as the guys who practice that are essentially doing the above.

 

[pcmfisher]

No, late hops are for flavour.

To adjust bitterness I'll tweak the kettle hops. I usually use a combination of two hops in the kettle, one with higher alpha than the other*. If I want to tweak bitterness by a unit or two I'll change their relative proportions to suit.

Edit: Yes to Killer Brew


* but both low by modern standards, I don't like the bitterness I get from the new triploid and tetraploid hop varieties.

Interesting that.
Which hops do you like for bittering? Sorry for the ot.

 

[Belgrave Brewer]

I was told that that isomerisation of hops stops at 80C. Does anyone know if this is correct?

 

[Lyrebird_Cycles]

I was told that that isomerisation of hops stops at 80C. Does anyone know if this is correct?

Near enough for Jazz. Isomerisation rate at 80oC is about 25% of the rate at 100oC. For further detail, see http://aussiehomebrewer.com/topic/91684-improving-precision-in-ibu-calculations/.

 

[Killer Brew]

I was told that that isomerisation of hops stops at 80C. Does anyone know if this is correct?

There is plenty of reliable info on isomerisation by time at boil however a lot less that I have been able to find on isomerisation at different temps. The below link is detailed but am not sure where they stand as far as a reliable source.

https://alchemyoverlord.wordpress.com/2016/03/06/an-analysis-of-sub-boiling-hop-utilization/

 

[Killer Brew]

Near enough for Jazz. Isomerisation rate at 80oC is about 25% of the rate at 100oC. For further detail, see http://aussiehomebrewer.com/topic/91684-improving-precision-in-ibu-calculations/.

That looks like some good research there LC. Hadn't seen it but will now set aside some time to look through.

 

[Lyrebird_Cycles]

Warning: Thread Drift

Interesting that.
Which hops do you like for bittering? Sorry for the ot.

I'm very, very old fashioned, I started brewing before the modern super alpha hops came out and I hated them when they were introduced.

I like Pride of Ringwood. There, I said it.

I also like the newer "summer" which to me has a soft long bitterness, especially if boiled for 90 minutes. These are my "go to" bittering hops for ales. For English ales I'll also use fuggles or EKG. For lagers I use summer and saaz.

 

[mikec]

Beersmith has the option of whirlpool/steeped additions and you set the amount of time the hops will be in contact with hot wort.
So if you chucked them in at flameout and had a 30 minute stand, you'd set those additions to WP/Steep, 30 mins.
The software then increases the bitterness accordingly in the recipe.

And yes, most isomerisation will stop below 80C.

 

[amarks6]

Many thanks guys for your very informative replies.

 

[Coldspace]

I no chill, but dump my cubes into my swimming pool to cool, they are usually cool in 30 mins so prob similar times to what you do,
I just a add my bittering additions in at 45 mins instead of 60. They seem to turn out excellent. I'm experimenting ATM with bittering additions in the 25 to 30 min range and going more hops. Get a smoother result.
I also love por hops , use it in my stout receipe for bitterness , comes up a treat. Go figure ,but they work in stouts as well as lagers/ales.

 

[Danscraftbeer]

I use beersmith but that doesn't have the calculations for my brewing now with Hop Stands.
Guestimations and record detailed notes is all you can really depend on the most I feel.

Eg. Whirlpool at flame out (~100c) and held for 30 minutes gets a decent wack of bitterness from the hops.
Hop stand at lowered temp like (75c) for 30 minutes will get a little if any significant bitterness.
I punch in a 30 minute hop stand at ~70c as a 1 minute whirlpool in beersmith. That seems to be right from my findings.

 

[Rocker1986]

I no-chill and I do absolutely nothing to the hop additions. I normally use hop additions at 60 mins, 10 mins and flameout to about 38 IBUs for APAs for instance; I input them like this in to Beersmith and it works for my tastes. I don't end up with over bittered beers or anything, even if the IBUs probably are higher than the software states. The beers may be a little less bittered if I chilled the wort straight after flameout, but I don't, so it's irrelevant to me.

It's one of those things that doesn't have one answer. Different things work for different people so just experiment and find what works for you, then stick with it.

 

[Danscraftbeer]

True that. It would be great to have an IBU meter as easy as having a hydrometer.

 

[Lyrebird_Cycles]

I punch in a 30 minute hop stand at ~70c as a 1 minute whirlpool in beersmith. That seems to be right from my findings.

In theory 30 min at 70oC should come out to about 4 minutes at 100 oC.