How to deal with boil off to get the target yield

[Ward Chillington]

So I'm looking at my next batch and I'm leaning towards a clone of Brooklyn Brewing Company's Brown Ale. The recipe is from the database here on Brewers Friend:

https://www.brewersfriend.com/homebrew/recipe/view/464370/brooklyn-brown-ale-clone

It calls for a 90 minute boil and based on my past batches, I have had issues hitting my target yield when I stick to the mashing guide lines. Simply put, I come up short. I believe this is due to evaporation during the boil and with this recipe calling for a 90 minute boil, I am anticipating an even greater loss.

So with an all grain recipe, how do you guys keep your yield on balance when your wort is being subjected to evaporation in the boil and absorption in the mash? Do you just add water to the boil to keep it in range? Do you hold back some of your strike water and sparge more when you're getting low?

 

[Ozarks Mountain Brewery]

when using another persons recipe don't follow their brewing method, use your boil amounts based on your kettle and profile, if you have to copy the recipe save it as your own and change it to how you brew

 

[Mark Farrall]

And using the copy method you can use the scale tool to adjust efficiency to cater for lower mash efficiency.

Then you just need to get your boil off rate in your equipment profile right. If you're not sure, go for a smaller boil off rate. Much easier to top up with boiled water if your gravity is too high than extend the boil for too low (affects your bitterness).

 

[White Haus Brews]

If you use the water calculator paired with your boil off rate you should know how much to start with.

That said, especially with all grain you may wish to brew to a gravity instead of a set volume. For example, if you take a gravity reading pre boil you will be able to figure out what volume to boil down to hit your target OG. Then time your hop additions appropriately.

But yeah if a set volume is more important than the OG then just use a water calculator that will include your boil off and grain absorption.

 

[Ward Chillington]

…..ok...so how do I figure out my kettle's profile? Farrell, what "scale tool"?

Is there a calculation that compensates for boiling surface area, relative humidity, time and elevation to give you some extra % of water to add? I'm pulling these variables out of my bung but I would think these are the sort of factors that are at play.

 

[J A]

If you've brewed several batches you should have an idea of what the boil-off rate is for you pot. As well as the losses in other parts of your system. If not, start taking some notes...you'll need that information to make any recipe work on your system.
Once you have a few data points you can set up your profile in the calculator and when you copy a recipe and edit it, it'll default to your values and you can make changes accordingly.
I think most of us just find the pre-boil volume that gives us the post-boil we need and use that number. A little trial and error is pretty invaluable.
And the errors are still beer!

 

[Nosybear]

Record the boil-off rate for several boils and average them. No statistical process control needed!

 

[White Haus Brews]

…..ok...so how do I figure out my kettle's profile? Farrell, what "scale tool"?

Is there a calculation that compensates for boiling surface area, relative humidity, time and elevation to give you some extra % of water to add? I'm pulling these variables out of my bung but I would think these are the sort of factors that are at play.

If you have a burning desire to know before your next brew and don't have notes on kettle volumes for your previous brews you could always do a dry run. Fill your kettle with about 4-5 gallons of water, boil for an hour, record before and after. Otherwise just take note next time you brew.

It will vary a little each time depending on boil vigor, humidity, etc... but you should have a pretty good idea after a few brews. And if more boils off than expected, just add some sterilized (boiled) water to the fermenter

 

[philjohnwilliams]

As others have said, experience and note taking will be your guide here. Along with experience, I have found a sight glass to be an invaluable addition to a boil kettle. I have mine marked with my pre boil and post boil levels (if doing this make sure to take into account the displacement of your immersion chiller, if you use one) and if I find myself getting too low during the boil then I top up with boiling water. Unless you boil in an indoor climate controlled environment, finding an exact boil off rate is trying to hit a moving target. Get as close as you can without driving yourself nuts, then adjust as necessary during the boil. I try to err on being a bit under my target volume, because I find it easier to add some water than trying to boil off some excess volume.

 

[Ward Chillington]

Haus! " you could always do a dry run. Fill your kettle with about 4-5 gallons of water, boil for an hour, record before and after. "Brilliant!

And I thought I was a smart guy! Thank you...now why the hell didn't I think of that?

 

[Nosybear]

Do a few runs under different conditions - particularly with propane, boil-off is not constant. But that procedure will get you in the ballpark.

 

[Hawkbox]

As others have said, experience and note taking will be your guide here. Along with experience, I have found a sight glass to be an invaluable addition to a boil kettle. I have mine marked with my pre boil and post boil levels (if doing this make sure to take into account the displacement of your immersion chiller, if you use one) and if I find myself getting too low during the boil then I top up with boiling water. Unless you boil in an indoor climate controlled environment, finding an exact boil off rate is trying to hit a moving target. Get as close as you can without driving yourself nuts, then adjust as necessary during the boil. I try to err on being a bit under my target volume, because I find it easier to add some water than trying to boil off some excess volume.

I hadn't considered this as my buddy who has a sight glass on his boil kettle actually has the water in the glass boil and its nearly useless. I just try to eyeball the markings inside the kettle, but that's an area I could definitely improve on.

 

[Ozarks Mountain Brewery]

you can get a shield for that

https://www.brewhardware.com/product_p/hs.sm.htm

 

[Nosybear]

I hadn't considered this as my buddy who has a sight glass on his boil kettle actually has the water in the glass boil and its nearly useless. I just try to eyeball the markings inside the kettle, but that's an area I could definitely improve on.

I use a dipstick - easy to read, convenient, and never boils.... Using propane, so much heat escapes around the sides of the kettle, I'm not surprised that the water in the sight glass is boiling.

 

[Hawkbox]

Yeah I run propane right now, at some point I'd like to go natural gas since it's already plumbed into my garage but I've spent enough on this hobby this year. He uses propane too and has a nicer rig than I do, somehow I manage to make better beer. At least so far.

 

[Nosybear]

Yeah I run propane right now, at some point I'd like to go natural gas since it's already plumbed into my garage but I've spent enough on this hobby this year. He uses propane too and has a nicer rig than I do, somehow I manage to make better beer. At least so far.

I switched to induction heating, a 3500 watt, 220 volt unit. Now I can brew indoors, if I'm willing to take the humidity. Sounding like next buy might be a hood or exhaust fan of some kind....

 

[Hawkbox]

If I could run 220v in my garage I would totally go that route. I need to talk to an electrician.

 

[Craigerrr]

I am pretty new at this, but as noted by others, do your best with the water calcs, and top up with preboiled water if necessary to hit your post boil volume. There will always be variations with time of year, humidity, etc., you will get comfortable with the calculations as you go. Did you watch the Youtube video i had posted a link to? That was the aha! moment for me with working out water requirements.

 

[Craigerrr]

Must have posted it elsewhere, Google the YouTube How to calculate water volumes for brewing, Mash Hacks

 

[J A]

Google the YouTube How to calculate water volumes for brewing,

There are tools and tutorials right here on the Brewer's Friend site. I'm not sure that new members understand the full extent of the resource that's available here.