Boiling just around the element?

[h22lude]

I just tested my new Spike kettle for boil off. I've been trying to get my boil off rate down. Even at 70% (using the brew boss controller) I was boiling off at 23%. This time I paid attention to how strong the boil was. I noticed that it was really only "boiling" over the element. The sides of the kettle weren't really moving. I assume this is normal (?) since the element is just in the middle but when I was using a propane burner the entire wort would bubble since the flame was covering the entire bottom.

 

[Smellyglove]

I use a induction top and also just see bubbles straight in the center, maybe 15cm diameter. I was worried about it first I noticed it, but as long it boils it boil, you will get movement in the wort.

With the propane burner I guess you heated up the entire bottom of the kettle.

I wouldn't be worried about it. Thousands of people boil with a heating element inside the kettle.

 

[dyqik]

It's fine, as long as the wort is being stirred around a bit by convection, and you are getting enough boil-off, which you are. I run at 2300W or so (~50% of 5500W) for 10% boil off in my Bayou Classic, and I really only get boiling from one end of the 5500W element.

 

[ZmannR2]

Ya I have a 5000W element and when boiling 14 gallons it isn't all that vigrous and I get 1.5 gal/hr boil off

 

[h22lude]

Thanks. I figured it was normal. I just never really paid attention to it.

I was able to get a 15% boil off 1.125 gallons). Im try to get a little lower but that's better than the 1.8 gallons I was boiling off before

 

[mabrungard]

As long as your wort is circulating in the kettle due to your boil, it is sufficient. I now boil with my kettle almost entirely covered and my power setting is about 20 to 25 percent for a 5500w element in 6 gal of wort. I can see trub gently circulating up near the center of the kettle and falling at the edges. I do uncover the kettle and increase the power in the final 10 minutes to drive off DMS. I am able to limit my evaporation to about 10 percent in an hour.

Remember, there is at least one example of brewing without boiling (Picobrew). They reportedly limit the wort temp to 209F and their system has a pump to circulate the wort.

 

[h22lude]

As long as your wort is circulating in the kettle due to your boil, it is sufficient. I now boil with my kettle almost entirely covered and my power setting is about 20 to 25 percent for a 5500w element in 6 gal of wort. I can see trub gently circulating up near the center of the kettle and falling at the edges. I do uncover the kettle and increase the power in the final 10 minutes to drive off DMS. I am able to limit my evaporation to about 10 percent in an hour.

Remember, there is at least one example of brewing without boiling (Picobrew). They reportedly limit the wort temp to 209F and their system has a pump to circulate the wort.

I remember reading one of your posts saying you started lowering your boil power. I couldn't find it. Glad you posted this.

My test was done with water so it was hard to see what was moving in the sides. I should retest and put something in that won't dissolve in water and will move around from the boil.

I was actually thinking about doing the same. 50 minutes on a low power with a small crack in the lid and then 10 minutes at a higher power with no lid.

My test yesterday I was at 45% power and about a 3" crack in the lid (probably even larger, I didn't measure). I may drop it to 35% and close the lid more.

Here is a video at 45% partially covered. Looked pretty low but there was still a good amount of movement on the surface.

https://youtu.be/ATGrTU2aMhk

 

[mabrungard]

Since the cover opening is only about an inch wide, I have to use a flashlight to see into the kettle and assess the boil vigor. This is just like the pro's since a lot of modern pro kettles have a light built into it.

I found that you don't want to lift the lid since there is a ton of condensate on the underside and it will sheet off onto what ever is around your brewing space. Using the flashlight keeps things more tidy.

 

[h22lude]

I'll have to test with that small of an opening. Hoping to get down to 10%.

I noticed that yesterday. Luckily nothing dropped when I carried the lid to my sink

 

[ba-brewer]

I remember reading one of your posts saying you started lowering your boil power. I couldn't find it. Glad you posted this.

My test was done with water so it was hard to see what was moving in the sides. I should retest and put something in that won't dissolve in water and will move around from the boil.

I was actually thinking about doing the same. 50 minutes on a low power with a small crack in the lid and then 10 minutes at a higher power with no lid.

My test yesterday I was at 45% power and about a 3" crack in the lid (probably even larger, I didn't measure). I may drop it to 35% and close the lid more.

Here is a video at 45% partially covered. Looked pretty low but there was still a good amount of movement on the surface.

https://youtu.be/ATGrTU2aMhk

Use a little bit of hop pellet or small pinch of crushed grain to help see the convection currents.

It took a while for me to get used to the look of the lower boil activity using electric. I reduced my 1.5gal/hour boil off with propane down to just under 1gal/hour but I still cant do the 10% thing without feeling nervous and bump the power up a bit.

 

[h22lude]

Use a little bit of hop pellet or small pinch of crushed grain to help see the convection currents.

It took a while for me to get used to the look of the lower boil activity using electric. I reduced my 1.5gal/hour boil off with propane down to just under 1gal/hour but I still cant do the 10% thing without feeling nervous and bump the power up a bit.

That's a good idea. I'm going to try this today after work. It was odd seeing little surface movement but just need to think this is normal. The higher powered boils are just wasting energy and causing the wort to darken more.

 

[mabrungard]

The higher powered boils are just wasting energy and causing the wort to darken more.

There are actually more maladies than that. Quicker staling, reduced head retention are others.

 

[h22lude]

There are actually more maladies than that. Quicker staling, reduced head retention are others.

That might explain why my beers never had good head retention.

Just tested again using 40% with a 1" crack for 50 minutes and then 50% with no lid. I put 10 or so grains in and could see them moving around. They would dip under water, move to the middle and come back to the side. I boiled off .8 gallons (give or take) and got my percentage down to 11.5%. I could probably use a lower power but I'm much happier with 11.5% than with my original 23%.

 

[Nmnbrewer]

I run my brew boss at 62% boil in my 20 gal spike kettle and I get around 1.25 gal/hr.

 

[BrunDog]

Cycle time on your duty cycle will also make a difference. Shorter cycle times are better as the element temperature swings are reduced, but this will put more stress on your electrical components, especially the SSR (generating more heat). Longer cycle times will result (at some point) with the boil around the element coming and going over the time of the total cycle. A net 2 seconds is a good compromise. At 50% it’s on for one second and off for another.

 

[Horseflesh]

I noticed and worried about the same seemingly weak boil issue in my electric kettle but everything works out fine. I have a 5000W element and my system is set to run at 100% power until it hits 207F, at which time power cuts to 55%. Boil off rate is a very reliable 1.6 gal/hr. That's for 5 gallon batches, btw, so initial volume is about 7 gal. During the boil the temp probe, which is far from the element, reads ~207-209F.

I could probably use even less power but I'm already using the system for smaller batches than intended, and want to keep my mash water in the ~8 gal area for most brews.

 

[Smellyglove]

Do you boil off 1.6 gal pr hour?

I do boil down to 16L, so small batches, but my boil off rate equals to about 0.47G/hr, about 9%.