What does it take for blow out?

[intense3123]

Let me start out by saying I'm very new to this game. Brewed my second batch this weekend. IPA extract with an 1.065 OG. Filled my 6 gallon carboy with a bit over 5 gallons since my last batch didn't quite produce the full 5 after transferring and hydro readings. When topping off, forgot to count for the fact that I also made my first starter that came out to about 800mL. So roughly had about 5 1/4 - 5 1/2 gallons in a 6 gallon carboy.

Thought for sure this one was going to blow over since it was a higher gravity, more wort, and I made a starter. Rigged up the blow off tube and small water bucket. Krausen did grow a good amount but stopped about an inch from the neck.

Not saying I wanted it to grow into the tube (more stuff I gotta clean out), but what does it take normally to warrant use of a tube?

 

[jsweet]

What was the yeast strain? That matters a whole lot...

 

[intense3123]

Wlp001

 

[smagee]

In my experience, the blowoff is triggered by a combination of three things: gravity, yeast, and color/type of beer. Gravity, obviously, is the biggest and most often cited factor--the larger the beer, the more likely it is to require a tube. That said, I do a lot of different brews in the 1.075-1.090 range, often side by side, and I've noticed that only my darker beers end up blowing off significantly. Right now I have a Belgian tripel that started at 1.087 happily bubbling away, but not really pumping out any material. Alongside it I have a Porter (OG 1.067) that blew off like nobody's business. Of course, they both use different strains of yeast, but I've had similar experience with batches that use the same yeast.

Long story short, if it's a light-colored beer, I almost never need the tube under 1.090ish. Darker beers, I always use a tube, because even weaker ones seem to need it.

 

[AmandaK]

Long story short, if it's a light-colored beer, I almost never need the tube under 1.090ish. Darker beers, I always use a tube, because even weaker ones seem to need it.

That's not my experience. I had a BDSA going with a OG of 1.107 and it didn't blow off. I used Wyeast 1388. My tripel (OG 1.080), which uses Wyeast 3522, blow off a lot. It's a light colored beer. In fact, when I brewed it last, it blew off three times. Ridiculous. Anything that I use Wyeast 3068 on, I use a blow off tube. That yeast is crazy! (And sometimes smells like dog farts...) It blows off no matter if it is a hefe or a dunkel. And those are around 1.045-1.056.

So I think it's more a matter of yeast than light/dark or high/low gravities.

I've had the 3522 and the 3068 blow off. The 1388, 1056 (or US-05/WLP001), 1098, 3789, 3278, 3763... not so much.

 

[JonM]

Use some Fermcap and that'll reduce the blowoff worries.

I still tend to use a blowoff tube whenever I'm making a big high gravity beer or using some new yeast I'm not familiar with. I recently got a surprise when using WLP400 for the first time. That stuff went nuts and got up into the blowoff tube despite the Fermcap.

 

[jsweet]

or using some new yeast I'm not familiar with.

+1. For my second batch, I tried Safale S-04. Had a heckuva lot of headspace, so I figured I'd be fine without a blowoff hose. Nope, went straight up and out my fermentation lock in <12 hours, while I was still sleeping!

That's why I immediately asked about yeast. I'm a total n00b, so I have no idea how WLP001 is in regards to this.