Goldings Single Hop Pale Ale

I just received a pound of US Goldings pellets, and I've been wanting something a little hoppier than the milds I've been making lately, so a pale ale it is.  


EDIT: Added 2oz. US Goldings dry hops after fermentation was complete.  CHange reflected in recipe below.

Calculated in BeerAlchemy

OG: 1.048
FG: 1.012
ABV: 4.8%
IBU: 41.4
Color: 5.3 SRM

Grain Bill
10.0 lbs. US 2-Row
0.5 lbs Caramel 40L

Hop Schedule
US Goldings - 2oz @ 60 mins
US Goldings - 1oz @ 30 mins
US Goldings - 1oz @ flameout
US Goldings - 2oz @ end of fermentation

Yeast
1 packet SafAle US-05

Water
1/2 tsp gypsum

Mash
Single-step infusion @ 152°F, 60 mins

Measuring SRM

I realize not many people have access to the necessary equipment to directly measure the color of a beer, but fortunately, I work in a research lab and have all this stuff sitting around, waiting to be used by curious brewers such as myself.  My most recent finished beer, an ESB, was just kegged and I've always wanted to try out the spectroscopic determination of beer color, so I though I'd give it a shot.
Wikipedia (which was the only source I could which gave the wavelengths needed for the process) defines the SRM (an acronym for Standard Reference Method - the output of the equation is in dimensionless units) of a beer as the absorbance at 430 nanometers times a constant and a dilution factor.

SRM = 12.7 * D * A, where D is the dilution factor (for an undiluted sample, D = 1, for a sample diluted 1:1 with deionized water, D = 2, 1:2 D=3, etc.) and A is the absorbance at 430 nm.

When I ran my ESB through, I got an absorbance of 1.36, which resulted in an SRM value of 17.3 -- what? An SRM of 17.3 is something expected from a dark lager, not a golden ESB. However, an EBC value of 17.3 looks right on, and conversion to SRM using the formula SRM = EBC * 0.508 results in an SRM of 8.8, which is close to the color calculated by my brewing software, 9.5.

Is Wikipedia wrong, or are my measurements incorrect? Does anyone have a reference for these measurements?

For those interested, here is my procedure:

1. Dispensed 35mL of beer into a centrifuge tube
2. Centrifuged at 10,000 RPM for 10 minutes
3. Passed supernate through a 0.3 micron syringe filter
4. Decanted filtrate to a small vial
5. Pipetted 3 mL into a plastic cuvette
6. Measured the absorbance at 700 nm (This measurement will tell you if your sample is clear of turbidity - a value under 0.039 times the absorbance at 430 nm means your sample is acceptably turbidity free)
7. Measured the absorbance at 430 nm

Results:
A(700) = 0.005784
A(430) = 1.36414

The Mash

Hello Internet, and welcome to The Mash, a beer, brewing, and fermentation-focused blog.

Before I was of legal age, I wasn't yet aware of the variety of beers available. Through mass media exposure, the only brews I was aware of were the standard macros, Guiness, Sierra Nevada, Sam Adams, and Leinenkugel's (my dad's suds of choice). The first time I walked into a liquor store, I was amazed by the array of six-packs they had - and what the hell are bombers and growlers? I walked out with 6 bottles of something I bought merely for the cool looking skeleton dude holding a brewski on the label, Rogue Dead Guy Ale.

And I haven't looked back since.

I began homebrewing because I wanted to try to make something that tasted as good as that first sip of a real craft brew - something hoppy, malty, and above all, flavorful. I'm not sure that I've succeeded yet, but I hope that someday my beer can make someone realize that there's a bigger, bolder, and brighter world out there than PBR tallboys and Corona.

And that's what brings me here - I want to share my thoughts on beer and brewing, recipes, techniques, reviews, etc. Like the mash of a brew session, I hope that The Mash can be the start of something great, but if not, hey, it's still beer, right?