Excessive foaming in the kettle
I have the problem of excessive foaming during wort boiling.
15 hl cup-formed kettle with 2 heating zones (steam). The heating zones are fitted as half-pipes. Boiling is done at atmospheric pressure. The vapours are transported by a fan and condensed in a vapour condensor.
Even with small batches of 8 hl the foaming problem is so intense, that I can hardly open the steam valve more than 50%. This results in very unsatisfying evaporation rate of 4 - 5% after 90 min of boiling. Opening the kettle door during boiling improves the situation a bit. The sucked in air is then helping to carry out the vapours more effectivly, but is off course also decreasing the performance of the vapour condensor. This is a problem, as uncondensed vapours go directly to the restaurant.
The foaming problem does not seem to be connected to any wort properties, as it occures with many different worts and different turbidity.
Last edited by schauf; 07-08-2003 at 10:40 PM.
Install a vent fan on the stack
Foam, Foam on the range!
I've had success in the past with a similar situation by dropping my first hop very early in the boil (5-10 minutes after start). However, this first hop amount is very small relative to all the others. Probably only about 2-4% of the next hop. This hop drop is also the same variety as the next. The idea is to get a small amount of the hop oils circulating in the boil to reduce boil over. Sounds like you also may be experiencing flue draw issues.
It sounds as though you are creating a vauum above your wort and are not actually needing to achieve 100 deg C + to boil. In order to draw the steam away with a fan and leave the kettle at atmospheric pressure , you need to allow air to pass into the kettle above wort level to act as the carrier - i.e. leave the door open. The vapour condenser just exacerbates the problem creating a semi sealed system. I have heard of instances of the wort being sent like a fountain from the top of the stack.
Try boiling with the door fully open, and adjust the steam to to give a 6 to 10 % evaporation / hour. I suspect you will get better performace from the heat recovery system as well.
Xssive in wortcopper
If you hop the kettle early at start of boiling (say 0 - 5mins), the hop oils will reduce the surface tension of the boiling wort, and thereby reduce foam formation. We are talking of bitter hops not flavor hops, which are added only a few minutes to end of boiling.
You may also look at the gravilty of the wort - high gravity worts tend to overfoam due to the same surface tension phenomenon. Please check. If you are boiling 18 oP and above, you must install a very good ventilator to the copper.
First- Vapor condensors dont work well. I had the same problem and now boil with the lid closed, but not clamped down. This allows for some airflow. I get alot of steam out the CIP arm as well. Even this was not enough though, especialy as i am pushing the 10bbl system to produce 10.5-11bbl by kettleing-up tp 13.5bbl
I have had good results with Fermcap by Sieble from Crosby-Baker. It knocks down that first rise of foam at start of boil and keeps it down. Adding a handfull of your bittering hops at start of boil does this too, but I think the fremcap works better throughout the entire boil. I doesnt stay in the beer and therefor is not an ingreadiant, and theoreticly gives better head.
As foam protiens form foam in the boil they are broken down when the foam breaks up. By limiting foaming in the kettle, and degradation of these protiens, the beer will have more foam capability in the end. A anti-foam product giving more foam! Weird but it works.
And about brewing steam in the resturant- Its a Brewpub! More than once i have repled to a waitstafs complaint of brewing smells by saying, "get anouther job" And customers- if they dont want to eat in a brewery they are in the wrong reasturant.
FermCap seems to be the answer to my problems.
Hops, even though given right 5 min after boiling starts never had the desired effect. While foaming is reduced initialy, the effect last only a couple of minutes. This is contrary to my experience as well, as usually foaming is only a problem until hops are added.
I also tried lowering steam temp./pressure which had some positive effect on foaming and allowed me to raise the evaporation rate to a just satisfying 7 per cent. However, the lower interface temperature at the heating plates caused a much lower protein precipitation and break formation, which I found not very desireable in regard of chem.-phy. stability.
I guess in the end it comes out to constructional issues of the kettle. Shape of the kettle, arrangement and size of the heating zones, and, probably most important, flue draw issues. However, these are expensive things to change, and if FermCap can help, it's very welcome . As I wrote, opening the kettle door a bit and providing some air to carry off the vapours does help to some extend. As I understand, its even compuslory with athmosperic boiling systems. However, the air acts as an insulator in the vapour condensor, and is lowering its efficiency dramatically. This means that I have to use very large amounts of water in order to condense the vapours to a reasonable amount. I don't mind smell and a bit of steam in the restaurant (after all its a brewery), but creating a turkish steam bath is a bit to much...
Well, again thanks everybody for the replies. I will try out FermCap, and post my experience here lateron.
Since you are in Europe, it may be worth trying other European suppliers for antifoams. I assume Fermcap is a silicone based antifoam. I do not remember hearing of its use in kettles, and therefore am not sure if all are suitable.
Closer to home, it might be worth trying AB Vickers, Dallow Works Derby, who make an antifoam used cold in FVs, yeast tanks etc, a product called FOAMSOL. FDC511.
It might also be worth giving one of you local bigger brewers a call asking them what and whose they use, if any, adn follong up from there.