Electric Kettle Sizes

[andy6026]

Hello everybody!

I'm currently an outdoor propane brewer, but I'd like to move indoors to an electric set-up in my basement, using the 3-kettle HERMS system. However, I'm having a lot of difficulty choosing kettle sizes.

My biggest concern is the size of my boil kettle. I'd really like to have the option of doing both 5g and 10g batches. Currently in my outdoor setup I brew 5g batches in a 15g kettle. While this is very comfortable, I still get the occasional boil over. I've tried a 10 gallon batch in the 15g kettle and it was nearly impossible to do without a boil over. However, I've heard that electric brewing allows for greater control. Can 10 gallon batches comfortably be done in a 15g electric kettle? A 20g might be the logical choice, but then I read that it is inadvisable to do 5g batches in a 20g kettle. Is that true? Argh!

So, in order to do 5g and 10g batches, would you recommend a 15g or 20g kettle? Please let me know what you've tried and what you advise.

Thanks ever so much!

 

[golfindia]

I use a 20g pot for 11 gal batches and an 8g pot for 5g batches. 5gal in the 20g pot barely covers the element. I use the 8g pot to heat sparge water for 11gal batches, and just switch the power cord. But if I'm only doing a 5g batch, I can heat up all the water at once in the 20 gal pot. So my answer is have a couple different size pots :^)

 

[mabrungard]

I use a 15 gal aluminum stock pot for my brewing. I do 5 and 10 gal batches. I converted that pot to electric with a 5500w wavey element and couldn't be happier. I also started covering my kettle more completely during boiling and that has helped reduce evaporation losses and heat stress on the wort. When I was boiling partially covered with about a 6" wide crescent opening, my power setting was at about 45%. Now I have reduced that opening width to about 1" and I had to reduce the power to about 20% to produce the same low boil vigor. I've also reduced the evaporative loss from about 15% to less than 10% in an hour. I need to get that down to about 8%, which is where most pro kettles operate. Boiling too hard and losing too much water is actually detrimental to beer quality. At 8%, DMS is still being effectively reduced.

Having a good proportional power controller on your heating element does help avoid incurring boil-overs. You definitely can produce 10 gal of wort in a 15 gal pot.

 

[stevehaun]

I went the 20 gallon route. Just make sure you put the element low enough that it is covered with a 5 gallon batch.

 

[highland_brewer]

I went the 20 gallon route. Just make sure you put the element low enough that it is covered with a 5 gallon batch.

Ditto... funny I just talked about that in my video series... lol

 

[cod3ck]

I use a 15 gal aluminum stock pot for my brewing. I do 5 and 10 gal batches. I converted that pot to electric with a 5500w wavey element and couldn't be happier. I also started covering my kettle more completely during boiling and that has helped reduce evaporation losses and heat stress on the wort. When I was boiling partially covered with about a 6" wide crescent opening, my power setting was at about 45%. Now I have reduced that opening width to about 1" and I had to reduce the power to about 20% to produce the same low boil vigor. I've also reduced the evaporative loss from about 15% to less than 10% in an hour. I need to get that down to about 8%, which is where most pro kettles operate. Boiling too hard and losing too much water is actually detrimental to beer quality. At 8%, DMS is still being effectively reduced.

Having a good proportional power controller on your heating element does help avoid incurring boil-overs. You definitely can produce 10 gal of wort in a 15 gal pot.

Not sure I understand-- isn't it ideal to have as much of a screaming boil as possible?

 

[JONNYROTTEN]

I also started covering my kettle more completely during boiling and that has helped reduce evaporation losses

I thought you cant cover the pot during a boil due to it "trapping" DMS for lack of a better way of putting it.
Please explain as this would be a game changer....Wouldn't everyone just cover there pots and have no need for ventilation/fans ETC...

 

[augiedoggy]

Hello everybody!

I'm currently an outdoor propane brewer, but I'd like to move indoors to an electric set-up in my basement, using the 3-kettle HERMS system. However, I'm having a lot of difficulty choosing kettle sizes.

My biggest concern is the size of my boil kettle. I'd really like to have the option of doing both 5g and 10g batches. Currently in my outdoor setup I brew 5g batches in a 15g kettle. While this is very comfortable, I still get the occasional boil over. I've tried a 10 gallon batch in the 15g kettle and it was nearly impossible to do without a boil over. However, I've heard that electric brewing allows for greater control. Can 10 gallon batches comfortably be done in a 15g electric kettle? A 20g might be the logical choice, but then I read that it is inadvisable to do 5g batches in a 20g kettle. Is that true? Argh!

So, in order to do 5g and 10g batches, would you recommend a 15g or 20g kettle? Please let me know what you've tried and what you advise.

Thanks ever so much!

With electric I brew both 5.5gallon and 11 gallon brews in my 3 kettle 15-16 gallon setup which has a 16 gallon bayou classic MT , HLT and a 15 gallon Bayou BK.. absolutley no problems because my kettles are only 15.5" wide and taller than they are wide (this increases your headspace a bit vs the cheaper wider kettles) . If you search the equipment section youll see someone else asked this same question like two weeks ago and there a bunch of discussion on it.

With electric and a boil intensity control boilovers are easily avoidable so its not an issue at all if you know how to control it (turning the element off instantly dissolves the building boilover before it reaches the top unlike a gas range or triclad kettle which retains the heat much longer ) Also with a variable boil controller such as duty cycle or pwm you can completely dial in the amount of boil off per hour consistently. Theres no need for guesswork.

 

[augiedoggy]

I thought you cant cover the pot during a boil due to it "trapping" DMS for lack of a better way of putting it.
Please explain as this would be a game changer....Wouldn't everyone just cover there pots and have no need for ventilation/fans ETC...

many people cover them until the boiling point is reached and then you leave them at least partially uncovered.

 

[JONNYROTTEN]

many people cover them until the boiling point is reached and then you leave them at least partially uncovered.

AHHH...I thought he meant the entire 60 minute boil

 

[JONNYROTTEN]

many people cover them until the boiling point is reached and then you leave them at least partially uncovered.

Actually the OP says covered during boiling

 

[augiedoggy]

Not sure I understand-- isn't it ideal to have as much of a screaming boil as possible?

Where did you hear that? all that does after the point of a decent rolling boil is increase your boiloff rate

 

[augiedoggy]

Actually the OP says covered during boiling

No he said "more completely covered " which to me as I understand it indicates (in a weird way of saying it) that its still not completely covered but he now covers it more than he used to..

 

[JONNYROTTEN]

Well lets go Mabrungard...Whats the verdict

If I could "sorta" cover my pot to save on steam in my kitchen it would be helpful.

Whats the limit on " more completely" covering without issue.

 

[Dolomieu]

I do 11-12 gal batches in converted kegs. If I had 20gal kettles I'd do 15 gal batches. There are ways of controlling boil overs.

 

[jcav]

I put 11 gallons of beer in my fermentor when I brew. I make and boil 13.25 gallons in my 15.5 gallon boil keggle with no problems with my electric brewery. After my boil is over I have 12.25 gallons left and I then can fill my fermentor with 11 gallons of trub free beer. After fermentation is over I can fill two 5 gallon corny kegs and have 10 gallons of finished product. It can be done. Dial in the power on your boil pid to like 70% or so and test it. You will find a happy medium between a rolling boil and a low boil off rate (mine is only a gallon in an hour) and you can control the boil overs as well.

John

 

[andy6026]

Thanks very much everybody. From what I'm learning the 15g kettle will certainly suffice. Also great to learn something else that wasn't the intention of the thread - that one can (and should?) partially cover the kettle during the boil. I also didn't know that one needn't boil as hard as the laws of thermodynamics will allow - very good to know that too!

Thanks again!

 

[mabrungard]

If I could "sorta" cover my pot to save on steam in my kitchen it would be helpful.

Whats the limit on " more completely" covering without issue.

I believe we all realize that virtually all professional systems are completely covered and have a vent stack. That is one point of evidence. In addition, there are plenty of results and textbook reports that say that evaporation loss from a properly running pro system is in the 6 to 10% range.

Now let's look at a typical homebrew system with no lid and modest boil vigor. Boil off rates of over 1 gallon per hour are pretty common in my experience. If you're starting with 6 to 7 gallons of wort and knocking off a gallon in an hour boil, you can see that the evaporation loss is in the 15 to 20% range. So, we can afford to substantially reduce our evaporation loss.

The big concern with boiling is to eject all of the SMM and DMS from the wort so that we don't have corn or cabbage bombs in our glass. Those volatile components are ejected from the wort in the same manor as water vapor. As evident from the pro's, we can afford to reduce that evaporation loss. There are homebrewers that have been exploring the lower limits of boil vigor and evaporation loss. Brian Rabe is one homebrewer that has conducted studies on this issue and he reports that 6% evaporation is iffy with respect to DMS effects. I've reduced my evaporation to 10% and had no problems, but Brian has mentioned that 8% is the sweet spot in his opinion.

Evaporation loss from a boiling liquid is a product of the liquid surface area and the exchange with the atmosphere outside the kettle. If the kettle is open, the exchange with the atmosphere can be high. It can be even higher if there is a breeze. When you restrict the exchange between the wort surface and the atmosphere outside the kettle, less steam vapor and heat is lost to the atmosphere.

The bottom line is that we can afford to cover our kettles more completely and reduce the evaporative losses. This issue is what I believe to be the largest difference between pro and homebrew systems. This has confounded homebrewers for quite a while...why can't their recipe just be scaled up for brewing in a pro system? Our concern over DMS and our quest for a vigorous boil has led us down the wrong path. Even our insistence on conducting 90 minutes boils when using pils malt is misguided since there are plenty of analytical and empirical trials that have found that an hour of boiling is enough for pils wort to not have DMS issues.

I recommend that you explore covered boils and reducing evaporative loss. For a 5 gal batch, that could mean reducing the volume loss to less than a half gallon in a 60 min boil. This will require reducing your starting wort volume, but that isn't hard.

 

[JONNYROTTEN]

I believe we all realize that virtually all professional systems are completely covered and have a vent stack. That is one point of evidence. In addition, there are plenty of results and textbook reports that say that evaporation loss from a properly running pro system is in the 6 to 10% range.

Now let's look at a typical homebrew system with no lid and modest boil vigor. Boil off rates of over 1 gallon per hour are pretty common in my experience. If you're starting with 6 to 7 gallons of wort and knocking off a gallon in an hour boil, you can see that the evaporation loss is in the 15 to 20% range. So, we can afford to substantially reduce our evaporation loss.

The big concern with boiling is to eject all of the SMM and DMS from the wort so that we don't have corn or cabbage bombs in our glass. Those volatile components are ejected from the wort in the same manor as water vapor. As evident from the pro's, we can afford to reduce that evaporation loss. There are homebrewers that have been exploring the lower limits of boil vigor and evaporation loss. Brian Rabe is one homebrewer that has conducted studies on this issue and he reports that 6% evaporation is iffy with respect to DMS effects. I've reduced my evaporation to 10% and had no problems, but Brian has mentioned that 8% is the sweet spot in his opinion.

Evaporation loss from a boiling liquid is a product of the liquid surface area and the exchange with the atmosphere outside the kettle. If the kettle is open, the exchange with the atmosphere can be high. It can be even higher if there is a breeze. When you restrict the exchange between the wort surface and the atmosphere outside the kettle, less steam vapor and heat is lost to the atmosphere.

The bottom line is that we can afford to cover our kettles more completely and reduce the evaporative losses. This issue is what I believe to be the largest difference between pro and homebrew systems. This has confounded homebrewers for quite a while...why can't their recipe just be scaled up for brewing in a pro system? Our concern over DMS and our quest for a vigorous boil has led us down the wrong path. Even our insistence on conducting 90 minutes boils when using pils malt is misguided since there are plenty of analytical and empirical trials that have found that an hour of boiling is enough for pils wort to not have DMS issues.

I recommend that you explore covered boils and reducing evaporative loss. For a 5 gal batch, that could mean reducing the volume loss to less than a half gallon in a 60 min boil. This will require reducing your starting wort volume, but that isn't hard.

What a great easy to understand detailed response.
I wasn't aware of the percentages the pros go by. I haven't taken pre/post boil measurements in a while. I'll have to do that to see what my percentages are. My next brew I'm going to try to figure out a way to rig up my lid so one side is below the rim for drip back and the other side is propped open. Sort of like a chimney flue damper.

 

[cod3ck]

I believe we all realize that virtually all professional systems are completely covered and have a vent stack. That is one point of evidence. In addition, there are plenty of results and textbook reports that say that evaporation loss from a properly running pro system is in the 6 to 10% range.



Now let's look at a typical homebrew system with no lid and modest boil vigor. Boil off rates of over 1 gallon per hour are pretty common in my experience. If you're starting with 6 to 7 gallons of wort and knocking off a gallon in an hour boil, you can see that the evaporation loss is in the 15 to 20% range. So, we can afford to substantially reduce our evaporation loss.



The big concern with boiling is to eject all of the SMM and DMS from the wort so that we don't have corn or cabbage bombs in our glass. Those volatile components are ejected from the wort in the same manor as water vapor. As evident from the pro's, we can afford to reduce that evaporation loss. There are homebrewers that have been exploring the lower limits of boil vigor and evaporation loss. Brian Rabe is one homebrewer that has conducted studies on this issue and he reports that 6% evaporation is iffy with respect to DMS effects. I've reduced my evaporation to 10% and had no problems, but Brian has mentioned that 8% is the sweet spot in his opinion.



Evaporation loss from a boiling liquid is a product of the liquid surface area and the exchange with the atmosphere outside the kettle. If the kettle is open, the exchange with the atmosphere can be high. It can be even higher if there is a breeze. When you restrict the exchange between the wort surface and the atmosphere outside the kettle, less steam vapor and heat is lost to the atmosphere.



The bottom line is that we can afford to cover our kettles more completely and reduce the evaporative losses. This issue is what I believe to be the largest difference between pro and homebrew systems. This has confounded homebrewers for quite a while...why can't their recipe just be scaled up for brewing in a pro system? Our concern over DMS and our quest for a vigorous boil has led us down the wrong path. Even our insistence on conducting 90 minutes boils when using pils malt is misguided since there are plenty of analytical and empirical trials that have found that an hour of boiling is enough for pils wort to not have DMS issues.



I recommend that you explore covered boils and reducing evaporative loss. For a 5 gal batch, that could mean reducing the volume loss to less than a half gallon in a 60 min boil. This will require reducing your starting wort volume, but that isn't hard.

This is awesome information, but assuming you had no concern of scaling, or hitting max possible volume, wouldn't the most vigorous boil possible still be advantageous?

 

[augiedoggy]

This is awesome information, but assuming you had no concern of scaling, or hitting max possible volume, wouldn't the most vigorous boil possible still be advantageous?

Why do you believe that to be true? What would it do better? If you heard that you must have heard a reason given?

 

[cod3ck]

Why do you believe that to be true? What would it do better? If you heard that you must have heard a reason given?

Can't remember where I came across this, so it may not be true -- but intuitively the higher the boil off rate, the more concentrated the wort, right?

Along with the wort concentration, I remember the idea being also to boil off as many bad chemicals as possible that may pop up in your tap water, so all that's left is sweet candy goodness! [emoji482]

 

[andy6026]

I believe we all realize that virtually all professional systems are completely covered and have a vent stack. That is one point of evidence. In addition, there are plenty of results and textbook reports that say that evaporation loss from a properly running pro system is in the 6 to 10% range.

Now let's look at a typical homebrew system with no lid and modest boil vigor. Boil off rates of over 1 gallon per hour are pretty common in my experience. If you're starting with 6 to 7 gallons of wort and knocking off a gallon in an hour boil, you can see that the evaporation loss is in the 15 to 20% range. So, we can afford to substantially reduce our evaporation loss.

The big concern with boiling is to eject all of the SMM and DMS from the wort so that we don't have corn or cabbage bombs in our glass. Those volatile components are ejected from the wort in the same manor as water vapor. As evident from the pro's, we can afford to reduce that evaporation loss. There are homebrewers that have been exploring the lower limits of boil vigor and evaporation loss. Brian Rabe is one homebrewer that has conducted studies on this issue and he reports that 6% evaporation is iffy with respect to DMS effects. I've reduced my evaporation to 10% and had no problems, but Brian has mentioned that 8% is the sweet spot in his opinion.

Evaporation loss from a boiling liquid is a product of the liquid surface area and the exchange with the atmosphere outside the kettle. If the kettle is open, the exchange with the atmosphere can be high. It can be even higher if there is a breeze. When you restrict the exchange between the wort surface and the atmosphere outside the kettle, less steam vapor and heat is lost to the atmosphere.

The bottom line is that we can afford to cover our kettles more completely and reduce the evaporative losses. This issue is what I believe to be the largest difference between pro and homebrew systems. This has confounded homebrewers for quite a while...why can't their recipe just be scaled up for brewing in a pro system? Our concern over DMS and our quest for a vigorous boil has led us down the wrong path. Even our insistence on conducting 90 minutes boils when using pils malt is misguided since there are plenty of analytical and empirical trials that have found that an hour of boiling is enough for pils wort to not have DMS issues.

I recommend that you explore covered boils and reducing evaporative loss. For a 5 gal batch, that could mean reducing the volume loss to less than a half gallon in a 60 min boil. This will require reducing your starting wort volume, but that isn't hard.

This is outstanding information indeed. Thank you!

One further question - how do you partially cover your kettle - have you made a cut in your lid or do you just leave it slightly to one side, or something else? Thanks again!

 

[mabrungard]

This is awesome information, but assuming you had no concern of scaling, or hitting max possible volume, wouldn't the most vigorous boil possible still be advantageous?

Up to a few weeks ago, I wouldn't have disagreed. But it turns out there is evidence in both brewing texts and journal articles that you CAN actually boil your wort too long and too hard. Do some searching for Thiobarbituric Acid and TBI (thiobarbituric index) and also review Kunze's text and you will find that excessive boil vigor and heating creates this staling precursor (thiobarbituric acid) that can damage your beer by oxidizing quicker.

In my opinion, there are still beers that benefit from a long boil like barleywines and other high gravity styles. That long boil should help accelerate that aged character that is important to those styles. But in other styles that don't rely on 'aged' character, it is clear to me that we don't want to boil too hard or too long.

We really need to rethink our approach to boiling and evaporation.

 

[mabrungard]

This is outstanding information indeed. Thank you!

One further question - how do you partially cover your kettle - have you made a cut in your lid or do you just leave it slightly to one side, or something else? Thanks again!

I just leave it slightly to the side. I was blessed when I bought my used 15 gal kettle off of ebay and they sent a lid that was too big for the kettle. I was pissed at first, but it sits on top of the kettle rim and I can move it to the side to create this 'crescent' shaped opening on one side.

 

[cod3ck]

Up to a few weeks ago, I wouldn't have disagreed. But it turns out there is evidence in both brewing texts and journal articles that you CAN actually boil your wort too long and too hard. Do some searching for Thiobarbituric Acid and TBI (thiobarbituric index) and also review Kunze's text and you will find that excessive boil vigor and heating creates this staling precursor (thiobarbituric acid) that can damage your beer by oxidizing quicker.



In my opinion, there are still beers that benefit from a long boil like barleywines and other high gravity styles. That long boil should help accelerate that aged character that is important to those styles. But in other styles that don't rely on 'aged' character, it is clear to me that we don't want to boil too hard or too long.



We really need to rethink our approach to boiling and evaporation.

Great information. Thank you!

 

[itsnotrequired]

i do 10 gallon batches (11 gallon into the fermenters) and use 20 gal kettles. i have not physically done a 5 gal batch yet but my elements are low enough that i could do it.

regarding cover on/off during boil, the brulosophy boys looked at this a few months ago and found little difference in the finished product:

http://brulosophy.com/2016/10/31/the-boil-lid-on-vs-lid-off-exbeeriment-results/

 

[BrunDog]

Yes but brulosophy tests often fail to find significance, even for experiments we know make a difference in outcomes.