Counterflow Chiller Bitterness

[6Trails]

Due to some water contraints at this time of year I'm thinking of switching back to by Grainfather counterflow chiller for a while to somewhat reduce usage. I've done a bit of Googling but can't find much on it, but has anyone ever seen anything about how much of an IBU increase that this type gives you vs an immersion style. I know IBU's aren't that concrete a thing but I'm at a point currently where I'm happy with what I'm getting back in bitterness vs the Brewfather calculations and it was just to see if I'd need to increase the AA values by 10, 20, 50% for a counterflow brew.
Another thought that had entered my head, though probably too simplistic, would be to have a large mash bag in for the boil and then pull it with all the hop matter at the end before chilling. Anyone tried anything like this? Thanks.

 

[MashBag]

I have never heard of a chilling affecting bitterness. Have I misunderstood your question?

Hop bags are available from most HBS

 

[The Baron]

I guess you are leaving the hops in and there may be some extra bitterness extracted with the extra contact time with the slower chiller which would contradict what you are getting as the counterflow should be quicker to cool so less contact time/less ibu extraction to 80c approx.
Whether it would make any discernible or noticeable difference I would think no.
But apart from that I can not throw any light on it

 

[MashBag]

Righto. That's makes sense. Extraction affected by chilling time.

I was reading it as a mechanical effect.

 

[6Trails]

I have never heard of a chilling affecting bitterness. Have I misunderstood your question?

Hop bags are available from most HBS

The thinking is because with an immersion you're getting all the wort in the kettle down below 70C fairly quickly in the process, but with a counterflow or plate you're only chilling what's in the chiller, and the wort in the kettle is still sitting at just under boil temps for the whole chilling process.

 

[The Baron]

You are right 6Trails I got it the wrong way around maybe but either way it is so quick to get to sub 80c it will be very negligible I would think to notice much difference IMO

 

[6Trails]

You are right 6Trails I got it the wrong way around maybe but either way it is so quick to get to sub 80c it will be very negligible I would think to notice much difference IMO

Probably needs a couple of repeat brews to see where I'm at really, I tried doing some sums this morning but I went that deep I forgot what I was actually calculating by the end

 

[peebee]

Ah ... I struggled with the idea of increased bitterness with a counterflow chiller too. Thanks to @MashBag and @The Baron I get that now.

But my own methods mean it could never happen anyway. Nothing unusual: I recirculate the initial cooling to get the temperature down for late (post-boil) and steep hops. So, I'd recommend the same thing; drop the temperature of the entire boiler contents to 70-80C before switching the output to the fermenter.

Actually, I did this to make it feasible to drop the temperature to pitch temperature in a single pass. And now I'm avoiding the issue by starting to use no-chill cubes to avoid excessive water usage (and an in-line "hop missile" - cheapskate's "hop rocket" - for the steep hops). Or at least I will, if I can get of me backside and finish doing it.

 

[MashBag]

@peebee spot on.
I was going to say the same. Time your hop routines and then chill.

Or in my case go and have breakfast and come back tomoz