How vigorous does the boil need to be?

[Follows]

I purchased an electric turkey fryer to use as my boil kettle. Ordered it from the US and it came damaged and used but that is another story. In testing it out, it boils water at a low simmer and the evaporation rate was 1/2 gallon over one hour. My question: does the boil need to be really vigorous or can I get by with a milder simmer type of boil?

[berley]

It definitely doesn't need to be hopping out of the pot, but it preferably should be a rolling boil.

Everyone's evaporation rate will differ slightly, but I usually can count on about 1.5 gallons over an hour, give or take.

[Tony L]

As long as it is moving around, as Berley says, it should be good. A more voilent boil would shorten the boil time in order to get your
required gravity. You need movement of the wort to get the hops to release as much of their goodness as you can. Also, boiling reduces the wort volume, so a better boil would do that in a shorter time frame.

[Follows]

When I was boiling up 2-3 gallons of extract on my propane kitchen stove I could get a rolling boil, but with the electric turkey fryer the water is slightly bubbling and not rolling over. So I'll try to return the turkey fryer unless someone wants it for heating up strike/sparge water. It heats up 6.5 gallons at a rate of about 1.5 F per minute. I paid $109 plus $80 for shipping, taxes, and duty.

[Tony L]

Have you tried it with the cover on.
There are a lot of guys using one of those to boil their wort with.

[Follows]

The cover will bring the water up to a stronger boil, but when I take the cover off the boil simmers down. I understand that one should not boil the wort with the cover on as it prevents certain undesirable chemicals from boiling off. Perhaps the one I have has a problem with the controller.

[Tony L]

From what I understand, you need the cover on but just leave a bit of space so the boil can let out DMS with the steam. And try to keep
any condensate from dripping back into the kettle.
Sounds like a lot of electric fryers used for boiling wort that I have heard about.

I have actually thought about buying one for myself for winter use, but don`t want anything else cluttering up my house.
My wife is about to kill me as it is with my brewing gear everywhere.