new burner numbers a bit crazy...help

[storytyme]

Hello everyone. There are numerous threads on this, but I honestly just need some quick advice as I don't have time to search and I want to brew tomorrow. I recently purchased the Bayou Classic KAB4 and put it through a test run to get boil off rate and to see what it can do.

Well, the first attempt it just burned all the paint off (which was expected) and then I ran out of propane.

The second attempt I got the flame dialed in to where I thought it should be (blue tips) and after getting the boil going my valve was on about 60%. It was much quieter than my old set-up and I thought I was going to loose the boil, but it went the whole 60 min fine. I started with 7 gal and finished with 4.5 gal! That seems like a huge loss based on my previous boil off rates (~20%). 36% loss is not good in my opinion and not even feasible if I want to do a 10 gal batch. I am using a 15 gal SS kettle. I also used 14% of my propane tank during the hour long boil. My brew coming up is a 90 min boil and the pre-volume based on these numbers is 15+ gal which my kettle can't hold.

Quick tips, thoughts, suggestions are appreciated. Thanks.

 

[ImNoExpert]

Sounds like you may be boiling too hard? if you back down the gas can you still maintain a boil?

I've heard that the KAB4 is a bit of a gas hog but even that sounds like a lot? What kid of pot are you using?

 

[GilaMinumBeer]

I've heard that the KAB4 is a bit of a gas hog but even that sounds like a lot? What kid of pot are you using?

Sounds like Mexican Red and a lost track of time.

 

[LandoLincoln]

Yes, the KAB4 with the 30 psi regulator is an incredible gas hog and puts out way too much heat. I would highly recommend changing the regulator to 20 psi. Would give you better control over the boil. Hardware stores often have them in stock.

Don't go by percentages when discussing boil off rates. Boil off doesn't work like that.

My advice to you is to monitor the boil off rate during the boil every 15 minutes and adjust the heat accordingly. If you're doing a 60 minute boil and you're expecting to lose 1.5 gallons in a 60 minute boil then you should be losing about a third of a gallon every fifteen minutes.

 

[day_trippr]

The burner in the Blichmann burner looks for all the world to be the exact same casting as used on the KAB4 and KAB6. Blichmann supplies a 10psi max adjustable regulator. I get a rolling boil - not overly vigorous - with the regulator set to roughly half its range, with roughly a gallon per hour boil-off.

Seems to me just because an adjustable regulator can go as high as 30psi doesn't mean it can't be throttled down to what makes sense.

A 2.5 gallon boil-off rate is crazy - I have to believe there was wort flying everywhere...

Cheers!

 

[LandoLincoln]

The burner in the Blichmann burner looks for all the world to be the exact same casting as used on the KAB4 and KAB6. Blichmann supplies a 10psi max adjustable regulator. I get a rolling boil - not overly vigorous - with the regulator set to roughly half its range, with roughly a gallon per hour boil-off.

Seems to me just because an adjustable regulator can go as high as 30psi doesn't mean it can't be throttled down to what makes sense.

A 2.5 gallon boil-off rate is crazy - I have to believe there was wort flying everywhere...

Cheers!

No, you certainly CAN throttle it down, but a 10 psi regulator is less touchy than a 30 psi regulator when you ARE trying to throttle it down.

 

[bu_gee]

Water and wort won't boil off at the same rate, though I don't know that you'll get that big of a difference.

Your boil-off rate is most affected by the diameter of your pot and the amount of energy you're putting into the pot.

If you used 14% of 12 lbs of propane, that is roughly 36,000 BTUs.

It will take roughly 7gal x 8lbs/gal x 160degrees = 8960 BTUs to bring 7 gallons to a boil from tap temp. Boiling off 2.5 gallons requires an additional 2.5gal X 8lbs/gal x 970 BTUs/lb = 19400 BTUs. For a total of 28,360 BTUs.

That would mean your efficiency was around 79% which isn't realistic. 50% would be fantastic. I usually assume 35-40%.

There is something wrong with one of your measurements or one of my assumptions by a factor of 2.

 

[Grannyknot]

I have a banjo burner with a 10psi regulator (Edelmetal)
I have a very wide kettle (lots of surface area) and boil off about 1.75gal per hour doing a very rigorous boil, which I do with pils malt.
I can dial it back and just have a gentle rolling boil and lose 1.25gal per hour.

I think bayou classic sells replacement lines with 10psi regulators on amazon if you feel like changing.

 

[LandoLincoln]

Water and wort won't boil off at the same rate, though I don't know that you'll get that big of a difference.

Your boil-off rate is most affected by the diameter of your pot and the amount of energy you're putting into the pot.

If you used 14% of 12 lbs of propane, that is roughly 36,000 BTUs.

It will take roughly 7gal x 8lbs/gal x 160degrees = 8960 BTUs to bring 7 gallons to a boil from tap temp. Boiling off 2.5 gallons requires an additional 2.5gal X 8lbs/gal x 970 BTUs/lb = 19400 BTUs. For a total of 28,360 BTUs.

That would mean your efficiency was around 79% which isn't realistic. 50% would be fantastic. I usually assume 35-40%.

There is something wrong with one of your measurements or one of my assumptions by a factor of 2.

It's not his measurements. I was also able to boil off 2.5 gallons in an hour with my KAB4.

 

[eric19312]

Water and wort won't boil off at the same rate, though I don't know that you'll get that big of a difference.

Your boil-off rate is most affected by the diameter of your pot and the amount of energy you're putting into the pot.

If you used 14% of 12 lbs of propane, that is roughly 36,000 BTUs.

It will take roughly 7gal x 8lbs/gal x 160degrees = 8960 BTUs to bring 7 gallons to a boil from tap temp. Boiling off 2.5 gallons requires an additional 2.5gal X 8lbs/gal x 970 BTUs/lb = 19400 BTUs. For a total of 28,360 BTUs.

That would mean your efficiency was around 79% which isn't realistic. 50% would be fantastic. I usually assume 35-40%.

There is something wrong with one of your measurements or one of my assumptions by a factor of 2.

I think he said he used 14% of a 20 pound tank of propane... about 60k BTU. 1k BTU needed to evaporate 1 lb of water. He evaporated about 20 pounds of water so efficiency is 33%. He must of used some energy to bring to a boil but if he weighed the tank at the beginning of the boil and at the end of the 60 min the values look reasonable.

 

[bu_gee]

It's not his measurements. I was also able to boil off 2.5 gallons in an hour with my KAB4.

I'm not saying it isn't possible to with the equipment. I'm saying that he measured one parameter incorrectly, so something is suspect here. I'm trying to help him figure out which one.

 

[bu_gee]

I think he said he used 14% of a 20 pound tank of propane... about 60k BTU. 1k BTU needed to evaporate 1 lb of water. He evaporated about 20 pounds of water so efficiency is 33%. He must of used some energy to bring to a boil but if he weighed the tank at the beginning of the boil and at the end of the 60 min the values look reasonable.

In the US, "20 pound" propane tanks that you swap at the store have been coming with 12 lbs of propane in them for at least 5 years now.

 

[eric19312]

In the US, "20 pound" propane tanks that you swap at the store have been coming with 12 lbs of propane in them for at least 5 years now.

Right...I was just pointing out a couple assumptions you made (12 pound tank) and (used the 14% of that tank to bring tap water to a boil and then boil for one hour).

If instead he filled his tank at a store that puts in 20 lbs and weighed the tank at the start and end of boil...33%

Or how about this one. An empty 20 pound tank weighs about 17 pounds. Filled that would be either 37 pounds (my tank) or 29 pounds (your tank). 14% of a 37 pound tank is 5 pounds...about 100k BTUs.

 

[storytyme]

The burner in the Blichmann burner looks for all the world to be the exact same casting as used on the KAB4 and KAB6. Blichmann supplies a 10psi max adjustable regulator. I get a rolling boil - not overly vigorous - with the regulator set to roughly half its range, with roughly a gallon per hour boil-off.

Seems to me just because an adjustable regulator can go as high as 30psi doesn't mean it can't be throttled down to what makes sense.

A 2.5 gallon boil-off rate is crazy - I have to believe there was wort flying everywhere...

Cheers!

It was just a trial run with water.......thank goodness

 

[storytyme]

I think he said he used 14% of a 20 pound tank of propane... about 60k BTU. 1k BTU needed to evaporate 1 lb of water. He evaporated about 20 pounds of water so efficiency is 33%. He must of used some energy to bring to a boil but if he weighed the tank at the beginning of the boil and at the end of the 60 min the values look reasonable.

I weighed by tank that was just filled and it was 37 lbs. When I finished the boil (plus the heating it up to the boil point) it was 32 lbs.

 

[storytyme]

Also, I thought it was a bit different with the 30 PSI regulator that it took so many turns to actually get propane flowing into the burner. Meaning, I open the valve on my tank 100%, and then started opening my regulator valve and no gas came out until around 4-5 turns. 11 turns it is open all the way. Is this how it should work??

 

[beernbourbon]

Also, I thought it was a bit different with the 30 PSI regulator that it took so many turns to actually get propane flowing into the burner. Meaning, I open the valve on my tank 100%, and then started opening my regulator valve and no gas came out until around 4-5 turns. 11 turns it is open all the way. Is this how it should work??

Don't know if this is how it SHOULD work, but that's what mine does as well. Always thought it a bit strange, but went with it.....

 

[LandoLincoln]

Don't know if this is how it SHOULD work, but that's what mine does as well. Always thought it a bit strange, but went with it.....

Or you could install a propane ball valve. That would take a lot of the guesswork out of the flow.

 

[storytyme]

Or you could install a propane ball valve. That would take a lot of the guesswork out of the flow.

Is this what you did? If so, did it make a big difference?

 

[LandoLincoln]

Is this what you did? If so, did it make a big difference?

No, I didn't, but I wish I had. I got so frustrated with never knowing how much heat I was applying to my kettles that I went and made an electric rig in my basement.

I'm betting that a ball valve would have worked a lot better than the stupid gate valves or needle valves that they come with, though.

 

[eric19312]

I weighed by tank that was just filled and it was 37 lbs. When I finished the boil (plus the heating it up to the boil point) it was 32 lbs.

So you used 5 lbs of propane - that would be 25% of the tank...

What temperature was the water when you measured 7 gallons and 4.5 gallons respectively. I always lose about half a gallon or even more after chilling the boiling wort and taking out the immersion chiller.

 

[storytyme]

So you used 5 lbs of propane - that would be 25% of the tank...

What temperature was the water when you measured 7 gallons and 4.5 gallons respectively. I always lose about half a gallon or even more after chilling the boiling wort and taking out the immersion chiller.

Is that a lot of propane for a single boil? What is funny is that I have done 50+ batches over the years and have never paid attention. I figured I should with a new burner.

Temp was about 81 degrees when measured at 7 gal. It was 205 degrees at 4.5 gal. When it cooled naturally it lost another .25 gal.

 

[eric19312]

Is that a lot of propane for a single boil?

It sounds about right to me. One tank good for about 4 boils.

I switched to natural gas a few months ago and now just use the propane for my grill. Don't miss dragging my tanks down to the refill store at all.

 

[storytyme]

It sounds about right to me. One tank good for about 4 boils.

I switched to natural gas a few months ago and now just use the propane for my grill. Don't miss dragging my tanks down to the refill store at all.

Wish I had the option of natural gas. That would be nice. I see electric set-up coming down the road.

 

[storytyme]

So I completed my first brew with this new burner and I learned a lot. I did a 10 gal batch and based on my huge boil off rate I had it at 14 gal in a 15 gal kettle to start. Before I get to the actual boil part, when I was heating my strike water I melted the plastic on the ball valve handle...not a great start. So on to the boil. I cranked it up to get the temp up (maybe 80%) and when it got around 208 I started to baby it. With about an inch from the top of the kettle I was a bit cautious. Well for the first time since my first couple brews 50+ batches ago I had a boil over. I shut it down, hosed off everything and tried again. Boil over again (although not as bad). As I went to light the burner the third time I realized it was still going. I am used to the old burner and the jet engine noise that comes with it. This KAB4 I couldn't even hear. I then easily got a nice rolling boil going and all was good. For a 90 min boil I lost 2.5 gal which included chill loss, so improved over my trial run. I just can't believe how quiet it was and throughout the boil I thought it went out, but nope. So this burner needs to be toned down....way down and when done so it is great.

With that said I took it to my Dad's shop to have him modify it a bit. I am going to bump the wind guard up to the supports and also move the burner itself to about 2" from the bottom of the kettle. Now it is about 5". Anyone else have modifications that have worked for them that I am not thinking of?

Thanks for all the advice on this. Just wanted to give an update on what happened. Cheers.

 

[bu_gee]

Didn't you say that you also lost 2.5 gal on your trial run? What has improved?

 

[storytyme]

Didn't you say that you also lost 2.5 gal on your trial run? What has improved?

The trial run was 2.5 gal in 60 min with no chill loss. This was a 90 min boil including chill loss. So usually .25 gal is lost in chilling so the boil lost 2.25 gal in 90 min or an hourly rate of about 1.5 gal......1 gal better!

 

[bu_gee]

Ah. I missed the 90 minute part.