Blackberry help

So my wife wants a blackberry beer...
Currently, I have a Brewer's Best American Cream Ale kit in my primary fermenter using Wyeast 2035(yeast with kit was bad and 2035 was available).
When I put the blackberry puree(that I boiled down the other day) in the secondary will I need a blow off tube? Will any flavor be scrubbed by fermentation or will it be negligible?

The puree will be a new source of sugar for your yeast to consume...use a blow-off tube...it's easier than washing off the ceiling...

It's always better to be safe then sorry and use a blow off tube.

As to flavors being scrubbed out. the yeast will eat most of the natural sugars that make blackberry sweet, so you will lose most if not all of the sweetness. If the wife want a sweeter brew, the best way to deal with this is to back sweeten with a sweetener that yeast can not ferment such as splenda. Rather than sweeten the whole batch, many people just sweeten selected bottles, or sweeten as they drink it. That way you don't accidentally over sweeten the whole batch, and can adjust each beer individually, or not at all to individual preferences.

Well, I racked it to the secondary. SG was 1.020. I added the blackberry puree.
I'm concerned though... When I opened the lid on the primary and stuck my nose down to smell it I got a nice nasal burn. Is that normal? Could that have been the CO2? Oxidation? It sat for 3 days with no airlock activity. Thursday night I added the Wyeast 2035 and the fermentation was fast and furious at about 65 or 66 for 2 solid days. Maybe too warm for a lager yeast?