Ok, so here's the deal.
I'm a biochemistry student who is now a lab technician at a microbrewery, replacing a person who has absolutely no experience or schooling in the field. As a BIC student, I also have no brewing background, but definately have the micro and chemistry to back up what I don't know, as well as the fact that I worked at the Beer Store for a number of years.
Since the tech before didn't know why a lot of tests are done, I too also struggle with this understanding, although many I have been able to reason out. My main question concerns the IBU's of beer and how to actually calculate them.
The procedure we use is simple; 5 mL of the beer being tested, 10 mL of iso-octane and 0.5 mL HCl, and it's shaken for about 2 minutes. The top layer is then removed and placed into the spectrophotometer at 275nm in a quartz cuvette, and then the absorbance reading is multiplied by 50 to obtain the IBU reading.
I struggle with having numbers from anywhere between 8-35 IBU, even on the same brews, which makes me wonder about the method. If I shake too hard or for too long, the IBU's go up; too soft or too short, and they go down.
I've tried to find answer in literature, but most I have found require resources we can't afford, or don't give good answers. I've contacted professors, but since they don't have brewing background, it's hard for them to fully understand.
Am I doing this right? Can someone help me? Even a simple "keep doing what you're doing" would suffice!
Cheers in good beers!
-Nikki
I'm a biochemistry student who is now a lab technician at a microbrewery, replacing a person who has absolutely no experience or schooling in the field. As a BIC student, I also have no brewing background, but definately have the micro and chemistry to back up what I don't know, as well as the fact that I worked at the Beer Store for a number of years.
Since the tech before didn't know why a lot of tests are done, I too also struggle with this understanding, although many I have been able to reason out. My main question concerns the IBU's of beer and how to actually calculate them.
The procedure we use is simple; 5 mL of the beer being tested, 10 mL of iso-octane and 0.5 mL HCl, and it's shaken for about 2 minutes. The top layer is then removed and placed into the spectrophotometer at 275nm in a quartz cuvette, and then the absorbance reading is multiplied by 50 to obtain the IBU reading.
I struggle with having numbers from anywhere between 8-35 IBU, even on the same brews, which makes me wonder about the method. If I shake too hard or for too long, the IBU's go up; too soft or too short, and they go down.
I've tried to find answer in literature, but most I have found require resources we can't afford, or don't give good answers. I've contacted professors, but since they don't have brewing background, it's hard for them to fully understand.
Am I doing this right? Can someone help me? Even a simple "keep doing what you're doing" would suffice!
Cheers in good beers!
-Nikki
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