Hop Bittering

[Ross]

I like to aroma steep my hops at the end of the boil - I used to remove the bittering hops (hop bags) & then add the aroma hops; but lately I've been leaving the flavour/bittering hops in to hopefully get a little extra (as making large late additions). I run my immersion chiller for a couple of minutes to bring it off the boil & aroma steep for 20 mins. But I've noticed a big rise in bitterness level. At what temperature drop do the hops stop adding bittering?

 

[joecast]

i think you are opening a huge can of worms here. i can just see brewers around the world checking hop alpha acid extraction vs. wort temp.
graphs, charts, thermometers being calibrated, oh the humanity!!!
joe

and just for the record, my guess would be the effect drops off rapidly as soon as the wort stops boiling. but...just to be sure.....

 

[Stuster]

Googled this for you Ross. It seems that there is not much info on it. Definitely a can of worms.

Link

Stuart

 

[Ross]

Googled this for you Ross. It seems that there is not much info on it. Definitely a can of worms.

Link

Stuart

[post="85388"][/post]​

Thanks for that - at least confirms my fears - Would be nice to see it in graph form, so you could work it out a bit closer. I reckon I'll have to go back to removing the hop bags - bugger...

 

[user 384]

Hi Ross

My understanding is that isomerisation is not just a function of heat, but is also dependent on the physical movement of the hops. This is achieved through a rolling boil. When you turn the heat source of the physical movemnet quickly stops and so does any significant isomerisation. I asked TDH from Grumpys about this. They brew 10 000 litre batches so their beer takes quite a bit of time to cool. During this time, the wort remains in contact with the hops. He said that once the boil was over this contact added little to the overall bittering.

I also wouldn't bother removing the bittering hops, as by the end of the boil, they've basically given up most of the bitterness. The increased hops utilisation bewteen a 60min boil and a 90min boil is negligible, so I would think the increased utilisation between a 60min boil and 30mins of the bittering hops just steeping would be even less. If anything is going to add to the bittering it would be the late additions, in particular any flame out additions, as the utilisation in the first 10-15 minutes is quite high in comparison. But as I already said, I doubt it would add much as isomerisation is a function of both heat and physical movement.

I would be looking at other reasons for the increase in bittering. Maybe fresher hops, maybe a harder boil, maybe an increase in flavour additions that increase the perception of bitterness.

Cheers
MAH

 

[Stuster]

Or just use less bittering hop at the start of the boil?

 

[Ross]

Hi Ross

My understanding is that isomerisation is not just a function of heat, but is also dependent on the physical movement of the hops. This is achieved through a rolling boil. When you turn the heat source of the physical movemnet quickly stops and so does any significant isomerisation. I asked TDH from Grumpys about this. They brew 10 000 litre batches so their beer takes quite a bit of time to cool. During this time, the wort remains in contact with the hops. He said that once the boil was over this contact added little to the overall bittering.

I also wouldn't bother removing the bittering hops, as by the end of the boil, they've basically given up most of the bitterness. The increased hops utilisation bewteen a 60min boil and a 90min boil is negligible, so I would think the increased utilisation between a 60min boil and 30mins of the bittering hops just steeping would be even less. If anything is going to add to the bittering it would be the late additions, in particular any flame out additions, as the utilisation in the first 10-15 minutes is quite high in comparison. But as I already said, I doubt it would add much as isomerisation is a function of both heat and physical movement.

I would be looking at other reasons for the increase in bittering. Maybe fresher hops, maybe a harder boil, maybe an increase in flavour additions that increase the perception of bitterness.

Cheers
MAH

[post="85406"][/post]​

It was more the late addition hops that I was worried about, as I'm aware the bittering hops are pretty well finished - I've started using 1 large suspended hop bag for making APA's, as it's far easier to make lots of seperate hop additions this way. If movement is an issue, then maybe the fact I continually agitate the bag to aid extraction during the steep, is causing the problem?
The extra bitterness is something I can easily adapt to - just prefer to have a better idea of what I'm going to get, before I taste it... :chug:

 

[Mr Bond]

I asked TDH from Grumpys about this. They brew 10 000 litre batches so their beer takes quite a bit of time to cool.

[post="85406"][/post]​

I think that that may be 1000 litres

 

[Darren]

Ross,
I agree with MAH. It is the late additions that are increasing the bitterness. Get yourself a CFC and add your late additions after you have drained off half your wort.

Just as a data point, the last time I brewed I wanted to collect some "sweet wort" for the kids. It had just come to the boil and before I knew it I had added the entire amount of bittering hops. I immediately decanted off about a litre of wort thinking the hops wouldn't have contributed any bitterness in the 30 seconds they were in there. I was wrong. The wort was very bitter. Gave some to my 6 year old daughter. All she could say is "bitter". So my experience is isomerisation at high temp is extremely rapid

TDH, MAH, do grumpys use much flavour or more so aroma hop additions? (stupid question probably)

 

[chiller]

Ross,
I agree with MAH. It is the late additions that are increasing the bitterness. Get yourself a CFC and add your late additions after you have drained off half your wort.

Just as a data point, the last time I brewed I wanted to collect some "sweet wort" for the kids. It had just come to the boil and before I knew it I had added the entire amount of bittering hops. I immediately decanted off about a litre of wort thinking the hops wouldn't have contributed any bitterness in the 30 seconds they were in there. I was wrong. The wort was very bitter. Gave some to my 6 year old daughter. All she could say is "bitter". So my experience is isomerisation at high temp is extremely rapid

TDH, MAH, do grumpys use much flavour or more so aroma hop additions? (stupid question probably)

[post="85419"][/post]​

From my experience with my system I have had to adjust my software to account for almost 25% more bitternes because i let my wort whirlpool for 20 minutes after flame out.

Late additions then theoretically are no longer late additions.

Steve

 

[nonicman]

I've been using this aroma hopping lately. Am I just growing accustom to highly hopped beers or does the bitterness from the steep addition fade from the beer at a faster rate than the bitterness obtained from the boiled hops (noticeable after 2 weeks in keg)? Possible reasonsing being that the steep component is not as stable as the long boil bittering?

Edit added question mark

 

[Tseay]

It's just an observation, but I have wondered whether baggng bittering hops reduces the impact of mechanical action on isomeration as opposed to allowing them free in the boiler. If this were the case then it might be possible that your increase in bitterness is simply an improvement in hop extraction efficency.

T

 

[Ross]

It's just an observation, but I have wondered whether baggng bittering hops reduces the impact of mechanical action on isomeration as opposed to allowing them free in the boiler. If this were the case then it might be possible that your increase in bitterness is simply an improvement in hop extraction efficency.

T

[post="85603"][/post]​

Tseay,

I use large bags made from fine net curtain material - I don't believe I lose anything detectable using these. I've run trials both ways & absolutley no difference detectable by my pallete.

From the answers here, it has been shown that some bittering does still occur after boil end that making large late additions with high Alpha US hops is no doubt compounding this - Therefore I will be making the necessary adjustments on future brews or removing the late additions from the kettle at flame out.

Thanks everyone for your input... :beer:

 

[tdh]

I brew 1000 litre batches at Grumpy's.
Sorry MAH, can't recall that conversation but my aroma additions are done very close to flame out.

I whirlpool for 30 minutes and it takes 60-90 minutes to chill.

I normally use lower alpha aroma hops for aroma additions so this and no rolling of the boil add little to the IBU level of my Grumpy beers.

tdh

 

[T.D.]

I have recently been steadily increasing the aroma additions of my beers (trying to push the limit a bit). I started putting in around 1 gram a litre of aroma hops, andmy last brew used 4 grams a litre. Even given this 4-fold increase in aroma additions, I have not noticed any change in bitterness (most of my beers sit between 35 and 40 IBUs). Just thought I'd throw a spanner in the works on the whole issue...