Ok gang, as promised, here is an update on my US/UK side-by-side yeast experiment:
I brewed this double batch on Superbowl Sunday, and racked from the primary today (day 6). Had a couple of guys taste with me - still early days, but a HUGE difference in all aspects of the profile and appearance of the two otherwise-identical beers. I started with 8.8 gallons of wort, boiled down to about 6.5. OG was 1.060, which was slightly stronger than what I had planned for. The two beers were fermented side-by-side at 68 deg. Overall, started as a good, solid, "APA" style beer as a base to really let the two yeasts do all the talking. And here is what they are saying...
English Ale batch WY1275 Thames Valley (3 gals):
This is becoming a flavorful, mellow, smooth beer with floral and sweet notes. Far lower flocculation, not as much attenuation. Gravity was 1.020 today, after 6 days. Still cloudy with yeast in suspension, although physical fermentation activity had appeared to have stopped. Lots going on in the flavor profile, great flavors, but almost "busy" with esters and other notes, and very much of a "British" character. Although frankly, I my choice of Ahtanum as a flavor hop doesn't seem to work very well with the prominent "english" flavors. (Will note that for the future...)
American Ale batch WY1056 (3 gals):
Far more flocculent, and even appeared to be a shade darker in the primary. Much more compact yeast cake on the bottom of the primary. Achieved higher attenuation with 6-day gravity reading of 1.013. Malt flavors were prominent in the American batch, almost loud compared to Thames Valley. All of us were surprised at the difference. This beer was cleaner, hops were able to carry through far better, and the yeast seemed cleaner, with little hint of esters. This beer just seemed more precise. (But of course it was exactly the same as the english batch)
Here's what WYEAST says about the two strains (btw I looked this up AFTER I wrote my impressions above, so let's see how I fared...
1275:
This strain produces classic British bitters with a rich, complex flavor profile. The yeast has a light malt character, low fruitiness, low esters and is clean and well balanced.
1056:
Very clean, crisp flavor characteristics with low fruitiness and mild ester production. A very versatile yeast for styles that desire dominant malt and hop character. This strain makes a wonderful "House" strain. Mild citrus notes develop with cooler 60-66F (15-19C) fermentations. Normally requires filtration for bright beers.
All seems pretty consistent with my findings, although the Thames Valley was fruitier/estery-er than they would suggest (Wyeast cites a fermentation temp range is 62-73, so my 68 deg ferm temp may have affected this). Was surprised that Wyeast claims that the American yeast needed filtration - doesn't seem to be the case so far in my experiment. All in all, this experiment is proving that the yeast makes a MASSIVE difference in the final beer. Also, converting the gravity into brix gives 3.3 for the american, 5.1 for the english batch. This measurement is corrupted a bit by the ethanol on the fermented beer, but directionally, if brix tells the % sugar in the wort, the english beer appears to have roughly 50% more unfermented sugars at this point.
More to come in about a week....