||04-30-2014 04:12 PM
WLP820 vs. WLP860 fermentation lag times
Quick blurb on the notoriously long lag time of WLP820. This will probably be my last time using it.
Last Sunday, 4/27/2014, I brewed 11 gallons of Oktoberfest. Recipe was similar to the BCS recipe:
6.5 lb each of Vienna, Munich 10L, and Pilsner
1 lb Caramunich 56L
1 lb Melanoidin malt
3 oz Hellertauer (60 min)
1 oz Hellertauer (20 min)
I mashed at 153 F for 1 hour, and boiled for 90 minutes. I ended up with approximately 10.75 gallons of 1.061 SG wort that I chilled via immersion to about 65 F in about 25 minutes, and then I tried to split it evenly between two carboys, which I placed in a chest freezer with ambient temp 48 F to chill to pitching temp overnight.
In preparation for this I made two starters over that week. First, I made a 2 liter starter of a single vial of WLP820 on a stir plate (manufacturing date 3/17/2014 - estimated viability ~70%). I then stepped that up to a 3 L starter without a stir plate, but with intermittent shaking. Using Brewer's Friend the estimated number of yeast cells using this method should be approximately 716 billion yeast cells, resulting in a pitch rate of approximately 2.3 M cells/ml/degree Plato for 5.5 gallons of my wort.
While the second step of that starter was propagating, I took the Erlenmeyer it was originally in, and made a 2.5 L starter for a single vial of WLP860 on the same stir plate (manufacturing date 3/10/2014 - estimated viability ~65%). This starter only had a SINGLE step, so this results in (again, using Brewer's Friend) approximately 463 billion yeast cells, which is a pitch rate of 1.5 M cells/ml/degree Plato for 5.5 gallons of wort. Thus, the starter of WLP820 is 80 M cells/ml/degree Plato HIGHER than this pitch rate.
I pitched the two starters on Monday afternoon (4/28/2014) around 6 pm after the wort temps had stabilized to 48 F. Attached is a photo of the two fermenters next to one another in the chest freezer from this morning (4/30/2014), approximately 36 hours after pitch. The fermenter with the high kreusen is the one with WLP860 (the LOWER pitch rate). Further, a quick pull from each of the two fermenters confirms that these visual fermentation symptoms accurately characterize what's going on: WLP820 is reading approximately 1.060, WLP860 is reading 1.055.
For those considering WLP820/WY2206 for their next lager, my experiences with this yeast are lackluster. It produces a lot of sulfur, doesn't clear quickly, and is notoriously slow fermenting when compared to almost any other lager strain. Hope this helps someone out there. My understanding is that the first generation of this strain (which this is) has some unpredictable results, such as long lag time and potential under attenuation. My suggestion would be to use more predictable strains like WLP830/WY2124 and WLP833, the second of which produces great malty beers.
||06-25-2014 05:44 PM
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