Fri Oct 15, 2010 6:29 pm
The yeast in solution will work, but it will take a lot longer. I haven't seen many homebrewers that has a full yeast/microbio lab set up yet, but when you grow yeast, optimally it should be at room temp (28C) with shaking between 225-250 rpm for at-least 16 hours but not much over 24 hours. If this is how you grew up your yeast then there should be a very little yeast at the bottom of your flask if any. With a stir plate you wont get the same oxygenation and then pitching the settled yeast will be better since the cells will be slightly more stressed.
If you want to try and "jump start" the yeasts again try to bring the temp around 70-74F and give it a little air, pull air lock swirl once plug back up. This should bring back some of the cells from stationary phase into growth/log phase and hopefully save the beer.
PS This is from a scientific background instead of homebrewing background. I grew yeast and bacteria in a molecular lab setting for the past 4 years by this method with great results, o.d. of greater than 0.6 when diluted 1 microliter of culture to 1ml.(the culture ended up looking like condensed chicken noodle soup and was thicker.)
On tap: dunkelwiessen, american brown ale
Fermenting: american barleywine
On deck: ? what ever is next