With the increased exposure to heat I would warrant the BU is 30-100% over your expected target.
I've raised this on the BS forum and had no answer. Using a photospectometer at current production plant the BU of all my beers were at least 30% over as the whirlpool addition does not contribute any BU - this is incorrect.
How does this relate to cube hopping - I used to formulate recipes the same way when making hundreds of wort packs a month, bittered at full from the 60 min addition with BS giving no BU for any whirlpool hops.
If u are using the 10 minute addition to add some BU I'd say this would still not be enough as the majority of iso-alpha would still dissolve leaving these to isomerise in the cube over time at the elevated temp. If ran thru the spectrometer I'd say all BU's would be over by a significant amount
The golden ale I make at work using a high alpha whirlpool hop is bittered to 6 BU with aprox 15-20 BU coming from the 10 min whirlpool and 45 transfer - imagine doing this and adding to a cube for 2 hours of a hot stand? The BU's would be through the roof.
Scotty
Ok, so this is starting to do my head in a bit.
Currently I am slow-chilling by submerging my cube in a 60L bin of cold water, previously I was using an immersion chiller.
the theory is that isomerization doesn't occur under 75C, so I can have all my hop additions including FO, or whirlpool without the BU's going through the roof.
Using the slow-chill, I can get the wort to under 75C within 30min easily, but this still adds an extra amount of bitterness to the brew.
The suspected reason for the elevated BU's in the slow chill is probably due to the 30min wait, while when I was using the immersion chiller it would get to under 75C in 5min.
The other reason would be due to thermal mass and inertia.
Even though my probe says its 75C on the outside of the submerged cube, it's not unreasonable to expect the centre of the cube will be hotter.
The problem I'm running into is that no-chill is all experimental STILL, and there is still a lot of guess work involved and no hard evidence that points to x amount of time =x amount of IBU at x temp using x AA hops.
There needs to be some measurable experiments done to measure the IBU's over a number of split boils using high and low AA hops (e.g. half chilled, half no-chilled = measure IBU's )
Until that happens, it's all going to be guess work.
Ideally I want to be able to slow chill with all my standard hop additions.
The only way I can picture this in my head is to use a 'bladder' submerged in chilled water with something that massages the bladder to keep the thermals moving and exposed to the cooler water.
the benifeits of this is you can dump your near boiling wort into the bladder, pasturising it within minutes, submerge to chill and store it away to ferment whenever you want.
on a commercial level, you could sell it the same as the wine packs...
Just something to chew on
BF
