When to go to Secondary?

[GrowleyMonster]

So, I have a 5gal batch of fairly strong all grain BIAB in a BMB, and I brewed it 13 days ago. I racked the wort right in on top of the trub from previous batch, and it took off like a race horse after two hours or so. It was extremely active with almost 3" of krausen on top and the airlock action was vigorous and constant. After a week it pretty much stopped, and then started again slowly. Today it is giving a bloop every 2 or 3 minutes. After pulling the bag, I sparged it with I guess 3 gallons of very hot water, and added a bit of extract, and ended up with 2-1/2gal of I think around 1.078 or 1.08 or somewhere around that. For yeast, I just dumped a pint of the other batch into this wort in another BMB, and it fermented still with a lot of vigor but not like the first squeeze, and never really shut down like the other batch. It, too, is down to a bloop in the airlock about every 3 minutes.

The trub level in the 5gal batch is pretty high, right under the spigot. I will have to use a racking cane because the spigot will suck out a lot of trub. Any "devil's share" of beer left on the trub will go into the second run. My main goal in two stage fermenting is to get better clarity, less sediment in the keg. I also want to get as complete a conversion as possible, of course.

Yeast is as I mentioned, the trub from a batch that had been moved from the fermenter earlier the same day. Parent yeast was US-05, fermentation temp was around 70 except for a couple of days when it got up to almost 75f cause GF said the house was too darn cold to run the AC and the yeast was going a little crazy.

Now my question is what should I be looking for, as a sign that it is time to take it to secondary? Should I wait until all bubbling has stopped, or move it to secondary while it still shows some activity?

 

[bucketnative]

The answer should probably be... "never."

Secondary is generally viewed as unnecessary step, left over from antiquated home brewing recipes and guides. Today, it is viewed as another chance for infection or oxidation. Secondary is only recommended for true secondary fermentations, such as fruit or other added ingredients (although, a lot of people do add fruit straight to primary... me included). Or, perhaps long-term aging on wood.

Very clear beer can be had using only a primary fermentation. Some use time/gravity, others this in combination with a cold crash, and some use finings. I don't think that there is much evidence of secondary yielding clearer beers these days.