Thoughts on boil-off rate?

[Bassman2003]

I too have been retrained when it comes to boiling. For some reason, as hombrewers we often come out of the gate thinking we need to boil the snot out of the wort. Like it is going to cleanse it or create those really malty beer flavors... Well, come to find out, boiling has a pretty limited role and just barely boiling temps are enough. Excessive heat or "thermal load" actually overcooks the wort and creates more harm than good. So just use a lid for partial covering and make it so the wort is gently turning over and you're good.

 

[Bigarcherynut]

I just came across a similar thread that linked me to this one. I've been brewing using BIAB for 6 years now. I've read forums all the time to help me understand all the aspects of brewing and has helped me brew great beers.

Back in the beginning, I read about boiling and what stuck in my head was boiling at or close to 212 degrees. Well I still do that by setting my controller in manual mode with an output of 100%. That gives me at temp of 211 degrees with my 4500 watt element. With that said, I set my brewing program to my current boil-off rate of 2.1 GPH. I'm shocked to see that I'm extremely high with my percentage of about 25%. Yikes!!!

My E-kettle is a unique shape. It's an oval which is 25.5" L x 13.25" W x 15.75" D with a 20 gallon capacity. My element is offset to one end and is about 2" off the bottom which is close to the 3 gallon level. I always have a good rolling boil and I circulate while boiling. My current mash thickness is from 2.5 to 3.0 Qts./Lb.

Now with my boil-off rate so high I need to adjust my power down but should I look at partially cover my kettle to get my numbers in the 4 - 10% line? I'll be curious to see if I notice a difference in flavor of one of my go to beers I make all the time.

Thanks for your input.

 

[balrog]

I don't E-brew so I cannot help with settings you might try, but I would turn that sucker down to save energy on the boil definitely. You really only need to boil enough to see that it is moving the wort. 25% is quite high for boil off rate. It'll save water too, but it'll make you recalculate your water requirements for your system, since you've been doing it many years.

Also, are you really recirculating during boil? That's awful hard on pumps, and why do you do that?

 

[Bigarcherynut]

I don't E-brew so I cannot help with settings you might try, but I would turn that sucker down to save energy on the boil definitely. You really only need to boil enough to see that it is moving the wort. 25% is quite high for boil off rate. It'll save water too, but it'll make you recalculate your water requirements for your system, since you've been doing it many years.

Also, are you really recirculating during boil? That's awful hard on pumps, and why do you do that?

I'm going to run a few test runs at different output settings to get a lighter boil and find what's works better.

I do recirculate. I have two pumps. One for circulating through my mash and one for circulating the wort under my false bottom. My kettle has a bottom drain on one end and my heating element is on the other end of the 25" long kettle. I circulate to make sure wort is well mixed and has equal temp throughout. I've done this from the beginning of my build and haven't had any pump issues. Well do far no problem.

Thanks

 

[Edd Mather]

I suppose I agree. I'm a stickler to myself for efficiency, but in the end the difference between beer and good beer would be worth it. Do you have an opinion on mash thickness and it's impact on certain characteristics? I've been trying to perfect my English Bitter lately and have read the they are made with a very thick mash traditionally..

Hi J Flint ,
Now for the fun part ; It depends on a few things does that nugget.
Firstly there is NO STANDARD GRIST for a UK Bitter Beer , then there`s the location in the UK of the style of Bitter you`re trying to do , but as a rule of thumb on beers under Ca 1.050 Gravity 1 St Heat & Ratio @ 2.685 L/Kg on 150 F , 2 Nd @ 1.075 L/Kg on 154 f and the third heat @ 158-160 @ 0.865 L/Kg , then sparge @ 3.865 L/Kg at no more than 15 f Liquor Heat above the last Mash Heat , Close the Mash Tun valve OFF @ 1.002 MINIMUM , for preference 1.003 on beers above 1.040 OG .
You`ll need to liquor back at collection from the mash tun but , you`ll also avoid drawing any nasties from the lower runnings .
Hope that helps ,
Cheers
Edd

 

[Bassman2003]

I also do not understand the recirc during the boiling stage. That is not normal practice and hard on your pump. I run a little boiling wort out to sanitize the spigot but not for temp control.

As for what you will notice - to my understanding, it is more about beer stability, staling and overall wort composition. Basically you are not killing the wort by over heating it. Some caramel flavors might be there with high thermal load but they are probably at the expense of other things. But, I always preface anything I say these days with - it is a hobby, your hobby and you should make any kind of beer, any way desired.

When I first started 16 years ago, folks were looking to buy jet engines to use as burners The prevailing thought was to boil the snot out. Well, the word is out that low thermal load it better in the end. You will need to adjust water and mash calculations as there is less shrinkage from the boiling stage. Meaning you need to the extract from your mash because your ratio will not change much after boiling much. i.e. there is not as much wiggle room to make up for low efficiency.

 

[LittleRiver]

...When I first started 16 years ago, folks were looking to buy jet engines to use as burners ...

I like the jet engine analogy!

I prefer a jet engine, it reduces the ramp time to heat mash water. With a quality adjustment valve on the gas, it's not a problem to throttle it down to produce a very gentle boil.

 

[Bassman2003]

Yes, Waiting for temperature rises is the biggest waste of time in brewing imho. My HLT has 8000w of electric elements. Sadly though, raising the wort to boil also needs to be low thermal lad, so that takes longer than I would like.

 

[Gduck]

Yes, Waiting for temperature rises is the biggest waste of time in brewing imho. My HLT has 8000w of electric elements. Sadly though, raising the wort to boil also needs to be low thermal lad, so that takes longer than I would like.

Personally I never mind the waiting as for me the brewday is a chance to have some quiet time and futz around in the garage. More important than ever for my sanity as I’m having to homeschool my kids for the foreseeable future.

 

[Bassman2003]

Difficult times for sure. Good luck with the new balance!

 

[Bigarcherynut]

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.

 

[Bassman2003]

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.

 

[Dog House Brew]

I generally run at 4% Boil Off rate.

 

[Bigarcherynut]

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.

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]

I generally run at 4% Boil Off rate.

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?

 

[Dog House Brew]

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?

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.

 

[Dog House Brew]

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.

 

[Bigarcherynut]

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.

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]

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/

 

[Bigarcherynut]

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/

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!

 

[Jeff...]

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.

 

[Deadalus]

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).

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.

 

[Mike_kever_kombi]

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?

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.

 

[Bassman2003]

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!

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.

 

[Bassman2003]

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.

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.

 

[cmac62]

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

 

[RPh_Guy]

What makes you guys think DMS is going to condense on the kettle lid?

 

[Jeff...]

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]

What makes you guys think DMS is going to condense on the kettle lid?

From my understanding, the steam carries away the bad stuff.

 

[RPh_Guy]

From my understanding, the steam carries away the bad stuff.

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.