Quantcast

Airlock Blowouts

Aussie Home Brewer

Help Support Aussie Home Brewer:

Bilph

Well-Known Member
Joined
26/1/05
Messages
140
Reaction score
0
I've just suffered my second ever krausen through the airlock saga, and was wondering what may have caused it.
I've had big headed ferments before and can generally anticipate them, so I can use a blow off tube or underfill the fermenter, but this one stumped me.
The main causes I've found in the past are:
Yeast - certain beasts are prone to big heads. Wyeast 1007 was my favourite. This was Wyeast 1318, another top cropper, but I've managed to control it before.
Yeast volume - overpitching, especially when using slurry can set a ferment off hot and fast.
Gravity - High gravity brews, especially stouts, have the krausen-climbing habit.
Temperature - Overly warm temps can extract a little too much activity out of the yeast.
Fermenter volume - An obvious one, but still relevant. Overfilling the fermenter increases the chances of a blowout.

The only other thing with this brew was the volume of dextrose. Slight miscalculation put about 700g of dextrose in the brew, which is more than I would normally use.

For the record, this was a simple quaffer variation. Beermakers Lager kit (sorry, but it was a freebie), 800g LME, 700g Dextrose, 175g Corn syrup. Hersbrucker hops. Wyeast 1318. Fermenter volume 23.5l. OG 1048. Pitching temp 22C. Ferment temp 20C.

As far as I'm concerned, none of the above really apply.
Any thoughts?
 

pint of lager

brewing on the verandah
Joined
9/5/04
Messages
2,287
Reaction score
11
Looks like you have nailed the common causes of big krausen.

Make sure that the fermentation temperature is the actual wort temperature, not the air temperature. Stick a sanitised good thermometer in to check what the temperature is. As you pointed out, 1318 is a top cropper, and will throw a head.

Trying to predict which will foam and which will not is a tricky business, especially when you use kit and kilo, as you have no control over what is actually in the malt, and your shop, or the ingredients manufacturer may vary what goes in the tins and bags.

I know a brewer that was making a big stout, had never seen huge krausen before, he came home at 11pm, found the plastic fermenter base bulged and the airlock blocked, so he pulled the airlock out of the top and spent the next hour cleaning his ceiling from the spray. Just what you want to do around midnight.

Easiest way is to always install a blowoff tube, put the fermenter somewhere so that excess foam will not be a problem and thank the yeasts for the marvelous job they do.

Or you could use lager yeasts.
 

Bilph

Well-Known Member
Joined
26/1/05
Messages
140
Reaction score
0
pint of lager Posted Today, 03:34 AM

Trying to predict which will foam and which will not is a tricky business, especially when you use kit and kilo, as you have no control over what is actually in the malt, and your shop, or the ingredients manufacturer may vary what goes in the tins and bags.
I think you've identified the problem. I've never used this tin before - I don't normally use tins anyway, and now I remember why.

I know a brewer that was making a big stout, had never seen huge krausen before, he came home at 11pm, found the plastic fermenter base bulged and the airlock blocked, so he pulled the airlock out of the top and spent the next hour cleaning his ceiling from the spray. Just what you want to do around midnight.
I always console myself with these pics when I worry about big krausen...
Exploding fermenter

I'm leaving mine to ferment with the lid off until she settles down...

Thanks.
 

Doc

Doctor's Orders Brewing
Joined
7/12/02
Messages
7,713
Reaction score
38
Location
Sydney
I've just had a blowout brew too. My Bier de Garde.
I put it down to not knowing the yeast (WLP011 Euro Ale) and not leaving enough headspace in the fermenter and an OG of 1.071.
I find they always make the best brews though :p

Beers,
Doc
 

Bilph

Well-Known Member
Joined
26/1/05
Messages
140
Reaction score
0
I gave this one a little more thought as I nursed it through a total of 3 blowouts through the day.
I suspect the problem was actually excessive yeast in the starter.
Normally I pitch the starter pretty much as soon as it reaches krausen. This particular starter I let brew out a little further because I wanted to taste it to make sure the yeast was still okay. In allowing the starter to brew about a day longer than normal I presume it would have produced more yeast in the starter, hence more yeast on pitching.
Case closed; unless my logic is flawed.
 

Latest posts

Top