How long has everyone's Barleywine taken to start its primary ferment after pitching yeast? Note: I didn't use a starter but did compensate by pitching two smack packs of Wyeast. I used English Ale 1098.
I do make a starter for all my beers. My last brew was a barley wine/strong ale, for which I used dry yeast that I first hydrated, and then added to a small starter of 1.020 SG, and the day after again. I pitched it and I got a proper fermentation in less than six hours.
On the other hand, I have also pitched dry yeast immediately on top of wort and only got a fermentation going after 48 hrs.
So I would suppose that using two such smack packs would need a time between 6 and 48 hrs before the fermentation has really started up.
Signs on the wort of beginning fermentation are small islands of foam. If you have a properly locked down fermentation vessel, you can of course follow the pressure on the air lock.