Rolling Boil Actual Temperature

[Boston85]

First batch is in the secondary now, but I had a lingering question from the brew a week ago. I know you want to keep a rolling boil, but what exactly does that mean? When I was adding hops, the water temperature ranged from around 170 - 210 degrees? Is this what it is supposed to be at? It was my first time, so I was not totally sure. Everything seems to be going fine now in the secondary, so I think I did it close to being correct, but I just had those questions about the actual rolling boil.

 

[BendBrewer]

Water boils at 212 degrees at sea level. Boston is pretty close to sea level. If it was boiling, it was 212 degrees.

I would get a new thermometer.

 

[ReverseApacheMaster]

Yeah, sounds like your thermometer sucks.

 

[TipsyDragon]

the thermometer doesn't suck it just need to be calibrated. unless you spend a ridiculous amount of cash any thermometer you get isn't going to be 100% accurate. to calibrate your thermometer boil some distilled water and take its temp. water boils at 212F minus 1F per 500 feet above sea level. i'm willing to bet your thermometer isn't going to say the right value. next stick some water in the freezer. check it ever so often. when it starts to freeze break the surface and let it freeze some more. when you have mostly ice slush take its temp. this temp i would expect to be closer to what it should be but don't be surprised if it isn't. now comes the math part.

correction factor = (boil reading - freezing reading)/(boil temp at altitude - freezing temp)

from now on multiply your thermometer readings by the correction factor.



now with all that said to answer your original question. as long as the wort is boiling when you add the hops your good. vigorousness of the boil really isn't an issue. i would be surprised if the wort was boiling at 170. next time wait till after the hot break before you start adding hops.

 

[Boston85]

Sorry that I was not more clear. I never actually had a full boil going. I think the thermometer is fine. I was just more curious if I was supposed to keep an actual full boil going throughout the whole process. Any time I started getting a full boil I would lower the heat. Next time I know I have to actually have a full boil going.

 

[Gremlyn]

Wort boils at more like 215F. Increasing the concentration of solutes in a liquid raises the boiling point, and you've got a metric butt load of solutes in your wort!

 

[TipsyDragon]

Wort boils at more like 215F. Increasing the concentration of solutes in a liquid raises the boiling point, and you've got a metric butt load of solutes in your wort!

true. i will agree with that. but as far as calibration of the thermometer goes distilled water boils at 212F

 

[Gremlyn]

true. i will agree with that. but as far as calibration of the thermometer goes distilled water boils at 212F

Oh sure, 100% pure water will and within our ability to measure at home, distilled water will as well. Your calibration method is sound, but it'd be nice to get a thermometer with calibration ability. I got one from Northern Brewer that is digital and can be calibrated.

 

[devilishprune]

Wort boils at more like 215F. Increasing the concentration of solutes in a liquid raises the boiling point, and you've got a metric butt load of solutes in your wort!

Yeah, when I did a boil the other day the surface of the wort was boiling and my temperature gauge was reading 216 consistently.

 

[DavidHawman]

My thermometer reads at about 215F whether I am at a vigorous boil or a simmer during the boil. I think many people base their boil at the evaporation rate and seek to boil off something like 10% of the volume over the 60 minute boil. I personally just get the boil to the point where the whole surface is moving, seems to work for me.

 

[WickedLB]

Sorry that I was not more clear. I never actually had a full boil going. I think the thermometer is fine. I was just more curious if I was supposed to keep an actual full boil going throughout the whole process. Any time I started getting a full boil I would lower the heat. Next time I know I have to actually have a full boil going.

Yes, you should keep it at a rolling boil the whole time. On a stove-top this can be tricky because of boil-over, but you can add some foam control drops and keep a spray bottle handy to knock down the foam.

 

[Gman2]

I have found that if i cover 3/4 of the top of the pot with tin foil it is a lot easier to control the temp and if it begins to boil over a slight adjustment to the position of the foil will increase/decrease the heat/foam level.

 

[dcamco]

Sorry to resurrect an old thread but I was wondering the same. I'm boiling right now at 221F. Just curious what everyone else was reading.

 

[helibrewer]

The other point to consider is the normal working range in which you use the thermometer. If you are primarily using it for mashing or monitoring the BK, then just calibrate it for boiling using distilled water. In all likelyhood when it's calibrated for boiling it will be a bit off for freezing and vice versa....so calibrate based on use.