overly agressive fermentation

Take it down slowly. Should be fine it you get down to 65-66F.

It is hard to pitch too much yeast.

You might have a beer with a lot of fusels and esters.

Next time pitch at 63-64F and let it rise to 68-70F. Both the liquid temp, not air temp.

 

Swap the airlock for a blow off tube, at least for the first few days of fermentation.
Your pitching temp is to high. Next time get it down around 65. I use a Rubbermaid box to keep fermenter cool. Put the fermenter in the box add water and, I use, frozen 2 liter bottles to cool the water. Basically the same thing you are doing in your bathtub.

 

5 gallons in a 6.5 gallon fermentation bucket can easily overflow through the airlock. I discovered this on my very first beer. Rig a blowoff tube.

I personally love my 8 gallon fermenting bucket. Although I suppose it's possible (maybe a big RIS?), I don't think many 5 or 5.5 gallon batches of beer are going to blow out the top of this one. Unfortunately, it's been out of stock here for a while, but I suspect some google-fu will find you one online without too much effort. I will likely buy a couple more of these in the near future when I buy another fermentation freezer/controller (which will happen as soon as my upgrade to ten gallons happens, I'm working on it now).

 

The wine bucket sold at most HBSs is 7.9 gallons, IIRC.

 

Blow-off needs to be accommodated. No big deal. The fact that you are getting blow-off is just an opportunity for you to report what is really wrong - your fermentation temperature. I brews IPAs at 62F for the first three days and then allow the temperature rise, about day 4, to 68. This produces the best beers for my process and yeast choice. I don't know what yeast you're using, but if you use one of the usual suspects 76F probably about 10 degrees warmer than optimal. That's serious. Your beer is not going to be the best you can produce. That's just the honest truth.

I stress these four things to new brewers:
You MUST pitch an adaquate quantity of healthy yeast (rarely do brewers over-pitch) into well oxygnenated wort.
You MUST control fermentation temperature.
You MUST limit aration of fermented beer.
You MUST use sanitary practices.

If you don't clean up well you may get lucky a few times before you get an infected batch. However, fermentation temperature is different. It is that it is not something that "might" affect your beer. It will affect your beer 100% of the time.

 

You have very accurately described the exothermic reaction of yeast fermenting. Your primary becomes a "space heater" when the yeast takes off.

If addition to your questions, I offer these tidbits:

If you pitched at 72 and placed your primary in 70 air, the wort most likely never reached 70. With a two degree differential in temp, it takes many hours (I'm guessing 12+) to change the temp of 5 gallons of wort. This emphasizes the importance of chilling to the correct pitch temp (maybe 1 or 2 degrees less). Once the yeast starts, the heat is generated and the battle starts. A water bath or fermentation fridge will need to be set 3-5 degrees cooler than your desired ferm temp. Of course you will decrease this differential as fermentation (and heat) slows.

You really want to get the lid sealed as soon as possible. Vinyl tubing 1/2" ID will fit over the center stem of a 3 piece airlock. Less desirable, but 5/16" ID will normally fit right into the airlock grommet. Most hardware stores have these sizes, you can go simple here, no need for food grade. Sanitize just like you did your airlock. The blow off will probably be ending by the time you get this set up, but you'll be ready for the next batch.

 

A few comments.

Firstly it is important to keep fermentation temperatures down during the first day or two. This is the timeframe when the majority of the fusels (higher alcohols) will be produced: for an ale, the peak rate of fusel production is somewhere in the range of 12-24 hours, with it starting to slow and beginning to approach the asymptote at around the 48-72 hour range.

A question which could be asked is: what is the big deal about a high amount of fusels? Fusels will produce a ‘hot’ taste and lots of folks report getting hangovers from just drinking 1-2 beers which have a lot of fusels.

I would suggest that you permit your IPA to further condition since one aspect of the conditioning process is that while in the presence of yeast the fusels that were produced during the first few days of fermentation can be processed by the yeast into esters. I would recommend that you leave the IPA in your primary for something like 3 weeks. If you bottle your beers the IPA can further condition in the bottles as part of bottle conditioning. Depending on how many fusels have been produced during the hot fermentation these fusels may be diminished a bit or optimistically diminished a lot.

Obtaining a 7.9 gallon bucket is easy. You can order them on-line from various vendors (Northern Brewer, Midwest Supplies, etc.).

Even fermenting in a 7.9 gallon bucket can result in blow off depending on the original gravity and fermentation temperature. Just this past weekend a Dubbel that I am fermenting (in a 7.9 gallon buckey) had a bit of blow off; the OG was 1.065 and the fermentation climbed into the low 70’s (I pitched at 64°F). As others have mentioned you can add a blow off tube to the stem of the three piece airlock. I just manage my blow offs (since they are minor) by simply removing the airlock and let some of the krausen seep out of the hole. For my recent Dubbel I experienced about ¾ of a cup of krausen material on top of the bucket lid.

I hope that your IPA turns out OK.

Cheers!

 

There's always a lot of talk of blowoffs when it comes to heavy fermentation, but I have opted for a more simplistic method which hasn't seemed to cause problems. If I predict a big fermentation (or I overfill my fermentor), I just throw on a piece of sanitized aluminum foil and let the krausen spill over a few times--making sure to clean up well each time. Once it settles, I throw on an airlock and wait. I've been doing this for about a year now and still haven't had contamination to my knowledge. I think enough CO2 is being forced out that nothing gets in to contaminate the batch. Anyone see an issue with this practice?

 

Another thought: does anybody regularly use Fermcap to control fermentations? If so, what are your thoughts on this product?

“Fermcap

A milky liquid emulsion that reduces foaming during fermentation, without affecting heading or the flavor of the finished beer. The active food grade ingredient, dimethylpolysiloxane, reduces surface tension of the wort, enabling you to have vigorous ferments in smaller fermenters. If you have trouble with your fermenter overflowing (particularly in warmer months) this additive is for you.

Fermcap™ settle out in the yeast sediment when fermentation ends. Use ¼ to ½ teaspoon per 5 gallon batch of beer, adding right before you add the yeast. Preserved with sodium metabisulphite. This 4 fluid oz. bottle is good for many batches and should be stored in a cool place, and shaken before each use to unify the emulsion.”

Cheers!

 

I use Fermcap in the boil for 10 gallon batches because it is easy to boilover in a keggle with a starting volume in the 13-14 gallon range. It is absolutely glorious for that purpose (and for boiling starters in the flask on the stove). I don't know and have often wondered if enough of it makes through the kettle trub and chiller and into the fermenter to help with blow-off. I've gotten into the habit of just always rigging a blowoff tube anyhow...sometimes I have krausen coming through it, sometimes I don't. Peace of mind, I guess.