Long(er) Primary Question on Priming

There should be plenty of yeast left in your RIS for priming. It doesn't take much. Unless you feel like the yeast you used may be up over its ABV limit and you want to add a yeast that does better in high alcohol environments, I wouldn't bother with adding any. You should be fine.

As for your second question, 68F should be fine for bottle conditioning and should not affect yeast viability. If I understand your question correctly, you are considering trying to adjust the carbonation level. If that's the case, and you're thinking of opening the bottles and adding some sugar (which sounds difficult to me, I've never done it), it wouldn't hurt to add a couple grains of dry yeast just for insurance, IMO. Whether or not this is worth the trouble would depend on how good the beer is and how inadequate the carbonation level is.

 

These two statements are not really compatible. How do you know it's done? Though my best guess would be that it probably is. But if the original yeast took your gravity down to where you expected it, they'll probably be more than up to the task of carbonating.

Yeast will remain quite viable at 68F if they have something to eat. (FYI - yeast remain viable longer at cooler temps. So 68F would never be too cool from a viability perspective. But it would be a terrible (high) temperature for longer term storage.) The mistake you made on your DIPA was (apparently) not using enough priming sugar. Just don't do that again. Under-priming and inadequate yeast are two completely different issues. You can't cure one by treating the other.

 

Q1: Should I pitch some new yeast before bottling to ensure proper carbing?

Yes. You probably underpitched your beer with 2 vials. Ideally, you would have made a starter to compensate for your yeasts viability. Your beer will still be tasty, but may take a little longer to shape up.

You are racking to secondary for the oaking, right? You should bottle the as is soon and you should make sure you fill to the neck of the 3 gal bucket on the one you are going to oak.

Q2: Could it be too cold for the remaining yeast to still be viable? Or is it too late and I'll have to deal with the very low carb?

3.6 Oz sounds like a fair amount of sugar for a 5 gal batch. That should have gotten you to around 2 CO2 volumes. (Top of my head). I'd guess that the yeast either capped out on alcohol and you should have tried some champagne yeast, or there was too long of a period between primary and bottling. Maybe with a high flocculating yeast you might have trouble.

Anymore, when I'm bottling a beer >7.5% I'm pitching fresh yeast into the bottling bucket. Usually, it's half a pack of whatever I was using, or half a pack of champagne yeast. You should properly rehydrate dry yeast and it will do fine as long as the attenuation is less than or equal to what you used for primary. The other half of the dry yeast pack can be saved in the fridge for priming or session beer.

 

How extended are you talking about? If you're just letting the yeast clean up their byproducts before bottling, they need to remain active. In that case, I'd keep the temps in at least the low 60's.

 

Re-yeasting a high ABV brew at bottling is cheap insurance.
Jamil recommends using about 1/10 the amount of the intial pitch.

Works for me.

 

After you pitch the 1/10 how long do you wait until bottling?

 

You pitch the insurance yeast right before bottling.

 

Thank you.

 

Not to put too fine a point on it . . . you add the yeast in the bottling bucket.