Yeast starters are widely advocated by homebrewers for all batches. The purported benefits include faster starts, quicker finishes, and more complete fermentations. This is a test to see if these benefits can be counted on for beers of normal strength and if the results are worth the additional work.
Yesterday, as planned, I made ten gallons of beer, which went into two separate fermenters. Both fermenters got exactly the same wort out of the same boiler, and both got the same yeast strain using two smack packs that were manufactured on the same day. OG was 1.056, which is toward the upper end of the range recommended by Wyeast for straight pitching of a smack pack. The date on the smack packs was March 3, several weeks prior to brew day. While I have occasionally found smack packs at my FLHBS that were only manufactured several days prior to purchase, several weeks seems pretty normal. Jamil’s starter calculator tells me that a smack pack of this age should have about 81% viability.
One fermenter got a smack pack that had been smacked at the start of the brew day. By pitching time about six hours later, it was good and puffy. I poured this directly into the fermenter and attached an airlock.
The other smack pack, though, I had smacked the night before and used to make a starter. I used 150g of light DME in 1500mL of water, boiled in a 2000mL flask and then cooled. I pitched the smack pack into this and placed the flask on my home made stir plate, where it spun until brew day was complete – about 20 hours. The entire contents of the flask were added to the fermenter, and an airlock attached.
This morning, about 16 hours after pitching, I checked the fermenters, which have been resting in my ferment fridge at 65 degrees. Both fermenters have a good solid inch of kraeusen, and both airlocks are bubbling actively. It seems like the airlock on the fermenter that got the starter may be bubbling a little more frequently than the other.
So, did one fermenter start more quickly than the other? Without having checked the fermenters hourly all night, I can’t say definitively that one started before the other. However, the lag time on both was short enough that they are well into high kraeusen the next morning. I would feel comfortable with the start time in either case.
I will continue to check the fermenters daily, and will report back on the questions of quicker completion and lower FG.