Thoughts on boil-off rate?

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Well after reading this thread, a thread linked to this one and another link on lower boil-off rates, I decided to do a test run on my system to see what I could end up with for a boil-off rate.

Here's where I have been and what I ended up with today after the test run.

Current boil-off rate - 2.1 Gal./Hr. This is with my controller set to 100% which gives me a temperature of around 210 - 212 degrees which I had read 6 years ago when I started BIAB brewing in regards to your boil. With this rate, my boil-off percentage is around 25% which is well above the 4-10 % which is talked about.

I developed my own brewing software program with the help of two designers that are on this forum. It is set for my unique home built E-kettle for BIAB brewing and is very helpful to have consistent numbers and brew great beer unlike in the past.

The last batch I brewed I started with 8.6 gallons of water and a post mash volume of 8.4 gallons. With the current boil-off style which is a huge rolling boil, I ended up with 5.85 which ended up with a rate of 2.75 Gal/Hr. Higher yet.

Today I started with a pre-boil water amount close to what my last batch had. I set the controller to 100% to get it to a boil. I did this with the lid on the kettle. Once the very rapid boil started with a temp of 208 degrees, I removed the cover, put a large baking sheet on the kettle with about a 1" gap in the back to vent. I reduced the controller to 50% output and monitored the boil. It was much less but still noticeable. I boiled like this for 30 minutes taking readings along the way. Temps where steady at 206 degrees. With this 30 minute run, I reduced my boil-off rate to .45 gallons for 30 minutes or .9 Gals/Hr. which would be about 12% boil-off rate. A huge improvement.

The next 30 minutes I reduced my output to 40%. The cover was left the same as with the first test run. The boil now was reduced to a mild simmer with still some mild movement of the water. My boil-off rate ended up being .3 gallons for 30 minutes or .6 Gal./Hr. giving me a boil-off percentage of about 8% which is in the range.

I'm going to brew the same beer again with the new boil-off method. Curious to see if there will be a difference in taste, especially mouth feel, which I seem to lack with some beers but make changes to improve that.

Input is appreciated.
 
Good for you. Testing is the only way to know. Please report back with your findings. I do not know if you will get any mouthfeel differences. It is better to not 'beat up' the wort in the long run and saves energy as well. Let us know how it turns out.
 
Bassman2003 said:
Good for you. Testing is the only way to know. Please report back with your findings. I do not know if you will get any mouthfeel differences. It is better to not 'beat up' the wort in the long run and saves energy as well. Let us know how it turns out.
Click to expand...

Almost 1-1/2 gallons less water, chemicals because I use RO water and one hour of electricity at only 40% power. That savings means more grains for more beer.
 
Bigarcherynut said:
To get lower I could maybe turn my power output down to 30 to 35% and cover my kettle more. Do you cover your kettle? Can you see any boil affect?
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I definitely have movement. I use NG w a 20tip jet burner, so I know nothing on electrical %. I bring it up and get a true boil until I get a good break. I then drop it down to where I get movement. I do cover my pot. It took me forever to get my % down. It went against everything I had always read. Boil hard for 90!! Crazy boil off numbers. My beers really improved not pounding the wort.
 
I will add that it isn’t an exact 4%. Always my target, but I’m also an outside brewer. Weather conditions also play a roll. I think the take is that it doesn’t have to be a driving boil.
 
Dog House Brew said:
I definitely have movement. I use NG w a 20tip jet burner, so I know nothing on electrical %. I bring it up and get a true boil until I get a good break. I then drop it down to where I get movement. I do cover my pot. It took me forever to get my % down. It went against everything I had always read. Boil hard for 90!! Crazy boil off numbers. My beers really improved not pounding the wort.
Click to expand...

For me I have a controller that I can run a PID loop control for obtaining and holding the mash temp but now I run it in manual at 100% till 2 degrees from my strike temp then shut it off, and my grains, stir like crazy and cover. I then set my controller to 5% output and it will maintain my desired mash temp. It's like a control knob on an electric range. I brew inside so I don't have to deal with temperature changes or wind. I may try some other settings and maybe the cover off to see if I can get it lower but I'm happy were it's at now. The hard boil is what I learned years back too. Hope this adds something to my beers.
 
Jim R said:
I recently listened to this discussion on the boil intensity. This PhD brewing professor seems to disagree with the idea of a lighter boil.

https://beersmith.com/blog/2016/03/...th-dr-charlie-bamforth-beersmith-podcast-121/
Click to expand...

Well according to Dr. Bamforth I've been boiling the proper way and anyone doing the low and simmer method is asking for trouble. I guess as he said, Vigor, vigor and vigor.

Sometimes I shouldn't read so much. It just gets confusing. Just like reading product reviews. Oh well, being confined in my house I didn't have anything else to do.

Stay safe!
 
I have a 20 gallon Chapman kettle. It's pretty large diameter. It took me a few brews to get used to it and it's large surface area. I use a propane burner and after getting used to it both. I can pretty much guess what my boil off rate will be.

If I do a vicious boil to carmelize some of the sugars in the wort it's around a 2 gallons per hour boil off rate.

However if I go for a nice easy rolling boil it's about 1 1/2 gallons per hour.
 
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Genuine said:
This is super interesting to me. I’ve been brewing on my electric system now for the past couple of years and I usually turn my controller down to 50-60% power on my 5500w element and I generally shoot for a gallon boil off in the hour long boil, which in my system is 14.3% . I’ve been wondering if boiling for a Lower boil off rate would be useful somehow (and save energy).
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Very similar, boil off a gallon from 7 to 6, most times in an hour. I start a little higher on the power (5500w) around 85% and check boil off rate over the first 30 minutes since I am outside and it can be cold sometimes. Then I turn it down as needed. Full power and the keggle is really rocking. Occasionally I'll boil off at a higher rate if I was asleep at the wheel sparging. I don't like to keep the power up above 90%, it just seems like the element is potentially too hot and seems to get a little crusty. I do hit it with 100% once the element is covered during the sparge but turn it down once it starts to boil.
 
Bigarcherynut said:
To get lower I could maybe turn my power output down to 30 to 35% and cover my kettle more. Do you cover your kettle? Can you see any boil affect?
Click to expand...

The thing to watch out for with covering the BK is boil over. If you have an extra large BK this is not too much of a problem, but if you are doing 5 gallon batches in a 10 gallon kettle, it can happen and happen fast.

I have a pretty small window on how much I can cover without ill effect. These are made up numbers but the effect is real. If I set controller to 42% output and have lid coverage of 15/32, I maintain a nice “low boil” with <10% boil off. If I cover 13/32 I cannot maintain temp and fall out of “boil range” rather quickly, if I come 17/32 it is boil over city.

You will need to fiddle with your system to see what the best output and coverage is to achieve desired results, if you are still looking to reduce boil off.

I noticed an improvement years ago in my monastic brews when I switched to to a lower boil off. The switch was unintentional however. I used to brew 20 gallons at a time, and used propane. I switched to NG to save some money on propane costs, but this came at the expense of heating capabilities. NG was not providing enough energy to achieve the vigorous boils I was getting with propane, so by necessity I had to partially cover BK to achieve any semblance of a boil.

The only precaution that I took is when I lifted lid (to add hops, etc) was to make sure I never let the condensation on lid fall back in to kettle. I would carefully remove lid to disturb as little as possible, then shake lid on to ground to remove the water droplets. I still do that as SOP inside on my electric system. Most of the recipes I brew have 90% plus Pilsen malt, and I have not had anyone reference DMS off flavors.
 
Bigarcherynut said:
Well according to Dr. Bamforth I've been boiling the proper way and anyone doing the low and simmer method is asking for trouble. I guess as he said, Vigor, vigor and vigor.

Sometimes I shouldn't read so much. It just gets confusing. Just like reading product reviews. Oh well, being confined in my house I didn't have anything else to do.

Stay safe!
Click to expand...
This is a tough area. It does seem the brewing industry has moved to lower vigor boils. I listened to a Brew Strong episode that focused on thermal load. They mentioned a new fangled way of passing a thin layer of wort through an evaporator which took the place of the boil. Sure, a lot of what the brewing industry does is for cost savings but they also act on wort/beer stability as well. High thermal load seems to damage the wort. What does that mean on the homebrew level? Very subjective. If you like your beer and you boil the snot out then keep at it. Maybe try a batch with a low boil off rate and see if any differences show up. This probably applies to lighter beers more than darker beers from a flavor perception point of view. Either way, it is an interesting topic and easy to experiment with on our level.
 
Mike_kever_kombi said:
The thing to watch out for with covering the BK is boil over. If you have an extra large BK this is not too much of a problem, but if you are doing 5 gallon batches in a 10 gallon kettle, it can happen and happen fast.

The only precaution that I took is when I lifted lid (to add hops, etc) was to make sure I never let the condensation on lid fall back in to kettle. I would carefully remove lid to disturb as little as possible, then shake lid on to ground to remove the water droplets. I still do that as SOP inside on my electric system. Most of the recipes I brew have 90% plus Pilsen malt, and I have not had anyone reference DMS off flavors.
Click to expand...

I made a custom lid with a sliding window so an open area can always be had for the steam to escape. Others have done this in the low oxygen brewing world (where I got the idea). Yes, it is important to let the bad stuff escape and also not condensate back into the boil.
 
I recently got a new system (more beer tippy dump) and the burners on it are the low pressure type and the boil in the BK I would call a simmer, not aggressive at all. I was thinking I will need to mod the system to upgrade the burners, but if the idea of this thread is correct I just need to adjust my pre-boil volume. That will be way easier than modding my system since I am not mechanically inclined. LOL :mug:
 
There only two times the lid goes on my kettle.

1) Bringing the wort up to just about a boil.

2) At flameout and untill all the wort is transfered into the primary.

Maybe I'm wrong... But I don't like all that wort I worked hard to produce sticking high up on the kettle walls and carmelizing.
 
Bassman2003 said:
From my understanding, the steam carries away the bad stuff.
Click to expand...
DMS boils off independently of the water (not carried by it) -- that's why we're able to reduce boil-off rate but still maintain adequate DMS removal.

The boiling point of DMS is 99°F, presumably well below the temperature of any water condensation on the kettle walls or lid during the boil. Therefore DMS won't condense there in any significant quantity.
 
I do not know but the lower boil rate still produces plenty of steam. I have heard brewers on podcasts speaking of poorly designed systems where the boil kettle does not have proper ventilation resulting in the condensation draining back into the wort and resulting in DMS flavors.

Here is an excerpt from a Craft Beer and Brewing article on DMS:

"When SMM is heated, such as during mashing or boiling, it begins to break down into DMS, but boiling actually drives much of it away. So boiling wort is good, and hot wort is bad. The moral? Boil like you mean it, and as soon as you’re done, cool that wort fast. And don’t cover the kettle during the boil or during cooling. All of that condensation that falls back into the boil pot is just dripping with DMS."

https://beerandbrewing.com/off-flavor-of-the-week-dms/
 
The Beer & Brewing quote is superstition or misunderstanding, not science.

Bassman2003 said:
I have heard brewers on podcasts speaking of poorly designed systems where the boil kettle does not have proper ventilation resulting in the condensation draining back into the wort and resulting in DMS flavors.
Click to expand...
Partially covering a kettle with a lid is not a "ventilation system". With the temperature of our kettle lid and walls being maintained well above the DMS boiling point, it will not condense in any appreciable quantity. That's like water condensing on a surface that's 350°F -- it doesn't happen.

That might not apply to a poorly designed commercial ventilation system with a long pipe because the temperature of the walls could drop.

DMS removal is one aspect of brewing where home brew scale actually has an advantage over larger scale commercial production. Our boiling wort has a much larger surface area to volume ratio, and therefore it boils aways much more readily.
 
Good news but I can't argue as I do not know. Never have heard about the low temp point of DMS. Seems odd that SMS needs to be broken down to form DMS yet the temperature for DMS to break down and disappear is only 30F degrees above room temps. It should never make it to the boil if the entire mash cycle is above its temp to break down.

Do you have any science findings regarding the SMM - DMS cycle all taking place below 100f?
 
Mike_kever_kombi said:
The thing to watch out for with covering the BK is boil over. If you have an extra large BK this is not too much of a problem, but if you are doing 5 gallon batches in a 10 gallon kettle, it can happen and happen fast.

Thanks for your reply.

I have a 20 gallon oval shaped kettle so for me, even with a 10 gallon batch I have no issue with boil over. I understand your concerns with condensation on the lid and adding hops. I may run another test and leave the lid off and lower the output to my electric element to see what rate I can obtain.

Thanks again!!
Click to expand...
 
Bassman2003 said:
This is a tough area. It does seem the brewing industry has moved to lower vigor boils. I listened to a Brew Strong episode that focused on thermal load. They mentioned a new fangled way of passing a thin layer of wort through an evaporator which took the place of the boil. Sure, a lot of what the brewing industry does is for cost savings but they also act on wort/beer stability as well. High thermal load seems to damage the wort. What does that mean on the homebrew level? Very subjective. If you like your beer and you boil the snot out then keep at it. Maybe try a batch with a low boil off rate and see if any differences show up. This probably applies to lighter beers more than darker beers from a flavor perception point of view. Either way, it is an interesting topic and easy to experiment with on our level.
Click to expand...

I understand what you're saying. Things do change all the time and I think that podcast was from 2016 and things change quickly. My stouts have been great and I did one with a 1.5 gallon batch that I boiled down to a quart for a carnalized addition. Worked great so I can see where a heavy boil for a stout like this is better. I recently starting brewing some Cream Ales and Scotch ales and think a lighter boil would benefit them. I'll be trying some lower boils for those.

Thanks!!!
 
For those of you following this thread, how many of you use a lid to partially cover your kettle and a lower heat to maintain a lower boil-off rate? My first test run at lowering my boil-off rate I did partially cover my kettle. After some of the later responses, I may try it without any cover but feel it may be impossible to lower my boil-off rate sufficiently without using the lid partially and still maintain a decide boil. Maybe I'm wrong so a test will help prove this.
 
Bigarcherynut said:
For those of you following this thread, how many of you use a lid to partially cover your kettle and a lower heat to maintain a lower boil-off rate? My first test run at lowering my boil-off rate I did partially cover my kettle. After some of the later responses, I may try it without any cover but feel it may be impossible to lower my boil-off rate sufficiently without using the lid partially and still maintain a decide boil. Maybe I'm wrong so a test will help prove this.
Click to expand...

I boil with the lid off and adjust the flame to maintain the desired boil off rate. Some styles benefit from a vicious blow up in you face boil mainly to carmelize some of the sugars. Other styles dictate a gentle boil. So I guess it depends on the brew style. I really don't believe how vicious or not the boil is applies across all beer styles.

I am interested in learning more about DMS. Though I've never had any problems with DMS in any of my beers before (that I know of anyways).
 
Jeff... said:
I boil with the lid off and adjust the flame to maintain the desired boil off rate. Some styles benefit from a vicious blow up in you face boil mainly to carmelize some of the sugars. Other styles dictate a gentle boil so I guess it depends on the brew style.
Click to expand...

Do you keep your rate in the 4-10% range?

I feel my stouts benefit but now sure about my cream ales and Scotch ales.
 
Bigarcherynut said:
Do you keep your rate in the 4-10% range?

I feel my stouts benefit but now sure about my cream ales and Scotch ales.
Click to expand...

Most of my beers average out around 6% but I have a 20 gallon Chapman Kettle. It's large diameter, so lots of surface area for evaporation. I can very easily bump the percentage well above 10 without even trying.

I would suspect at a higher boil off rate your carmelizing some % of suagrs in your wort. Which would show up in your finished beer.
 
Bassman2003 said:
Good news but I can't argue as I do not know.
Click to expand...
I'm here to learn and to teach, not to argue.
Bassman2003 said:
Never have heard about the low temp point of DMS.
Click to expand...
https://pubchem.ncbi.nlm.nih.gov/compound/Dimethyl-sulfide#section=Boiling-Point
Bassman2003 said:
Seems odd that SMS needs to be broken down to form DMS yet the temperature for DMS to break down and disappear is only 30F degrees above room temps.
Click to expand...
SMM conversion to DMS is a chemical reaction that requires heat.
DMS removal is a physical phase change (boiling/evaporation); it doesn't not "break down"; it just floats away as a gas.
Bassman2003 said:
It should never make it to the boil if the entire mash cycle is above its temp to break down.
Click to expand...
Most of the DMS formation happens above typical mash temperature.

No-boil beers are not loaded with DMS.
Bassman2003 said:
Do you have any science findings regarding the SMM - DMS cycle all taking place below 100f?
Click to expand...
DMS is pretty volatile (it's one of many volatile sulfur compounds) and so most of the DMS that remains in the wort after the boil is blown off with CO2 evolution during fermentation.
https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-37-0020

See here for a good discussion with references
http://www.milkthefunk.com/wiki/Dimethyl_Sulfide

Bigarcherynut said:
how many of you use a lid to partially cover your kettle and a lower heat to maintain a lower boil-off rate?
Click to expand...
I do. Using a lid definitely helps lower the amount of heat needed to maintain wort circulation.

If I want caramel flavors, I use caramel malt. I don't wreck my wort trying to add those flavors in the kettle.
 
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Jeff... said:
I would suspect at a higher boil off rate your carmelizing some % of suagrs in your wort. Which would show up in your finished beer.
Click to expand...
I never took chemistry but I have done a lot of cooking. Am I wrong in thinking caramelization does not happen at all at boiling temperatures? I have been confused by talk of caramelization ever since I read about the idea when I first started brewing.

Caramelization or caramelisation (see spelling differences) is the oxidation of sugar, a process used extensively in cooking for the resulting nutty flavor and brown color. Caramelization is a type of non-enzymatic browning reaction. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor. The reaction involves the removal of water (as steam) and the break down of the sugar. The caramelization reaction depends on the type of sugar. Sucrose and glucose caramelize around 160C (320F) and fructose caramelizes at 110C (230F) https://www.scienceofcooking.com/caramelization.htm
 
InspectorJon said:
I never took chemistry but I have done a lot of cooking. Am I wrong in thinking caramelization does not happen at all at boiling temperatures? I have been confused by talk of caramelization ever since I read about the idea when I first started brewing.

Caramelization or caramelisation (see spelling differences) is the oxidation of sugar, a process used extensively in cooking for the resulting nutty flavor and brown color. Caramelization is a type of non-enzymatic browning reaction. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor. The reaction involves the removal of water (as steam) and the break down of the sugar. The caramelization reaction depends on the type of sugar. Sucrose and glucose caramelize around 160C (320F) and fructose caramelizes at 110C (230F) https://www.scienceofcooking.com/caramelization.htm
Click to expand...


look up the difference between dry heat and wet heat, it's more complicated then just temp......


otherwise i wouldn't have to kiln my malt at 150-160f to make it taste good, when i plan on boiling it at 200+f.....
 
RPh_Guy said:
It's actually Maillard reactions that are occurring in the boil.
Click to expand...

Thanks for the correction I only know what I know by experience...

Take 1/2 of your wort and boil it viciously, the other 1/2 nice gentle rolling boil, pitch both independently with the same yeast and ferment independently. I can guarantee you'll have different beers when finished. I actually did this once when I was trying to teach myself how to brew. The little experiment taught me a lot about my behavior and how it impacts the brews I brew.

I guess what I'm trying to say is heat does matter. The difference is that little knob on my propane tank, that I control. If I boil the crap out of the wort, it's going to produce a different beer, than if I was gentle with the wort during the boil. Hope that makes sense?
 
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If anyone wants Maillard products, you can add some amount of melanoidin malt, or even some dark Belgian Candi syrup. This way you can still use a gentle boil to maintain fresh grain flavor.
 
Thanks for the links and info. The Wiki points to the cooling stage as being what is most important. DMS always gets associated with boiling but boiling is going to happen no matter what and the DMS evaporates quite easily at brewing temperatures. SMM is really the culprit and its breakdown is more associated with boiling temps.

Key takeaways:

SMM is largely not broken down into DMS until the boil
High pH in the boil helps this conversion
Reinforces the practice of higher pH through the mash & boil and lowering pH right at the end of the boil
DMS will be evaporating all the way through until sub-99F is reached (huge boil not needed)
Chill to 140F and below quickly as SMM is still being converted but DMS also needs motion to be "pushed" out of the wort
 
Bassman2003 said:
High pH in the boil helps this conversion
Click to expand...
Just to elaborate a little, 5.4 or higher is good at the start of the boil, and 5.1 is a good target for finishing. Some software like Mash Made Easy have kettle pH calculators built in.

Bassman2003 said:
Chill to 140F and below quickly
Click to expand...
Chill quickly below 176°F (85°C) to minimize DMS production post-boil, not 140°F.

Bassman2003 said:
huge boil not needed
Click to expand...
To get back on topic, only about 4% boil-off is needed for 90% DMS removal according to calculations.
 

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