Need some volunteers....

I'm getting ready to start a little study on boil-off rate, and hopefully with a few brew sessions worth of data I can come up with some kind of rough formula to get a decent estimate on evaporation rate.

Scientifically, figuring evaporation rate is next to impossible--considering you need to enter so many variables in the formula--volume, wind speed, temperature, surface area, relative humidity, etc. However, I think if I get enough hard data I can come up with a table and extrapolate some data to get in the ballpark.

I'm taking this project on because my evap rates vary so much and I struggle with my efficiency rates from season to season when the RH values differ greatly. I need some kind of guide to fix that.

So......to make a long story short, I'd like a few volunteers who brew frequently (1-2 times a month or more), who keep decent notes, and who can possibly help with the formulation of this "table".
If you are interested, you can PM me and I'll provide more details on what I am going to try to do.

Basically I'm going to record the relative humidity (I believe this is the biggest factor in the equation) at brew time, measure boil-off rate per hour and then put the numbers together in a table and extrapolate between extremes to get an accurate percentage of boil-off rate. I could do the study myself but if I had helpers we'd get much more data in a shorter amount of time.

Sorry for the long post.....

what kind of equipment is needed?

billybrew said:

what kind of equipment is needed?

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A pencil and maybe access to the internet to get your local relative humidity reading.

ORRELSE said:

A pencil and maybe access to the internet to get your local relative humidity reading.

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I don't think I have access to the internet...can I still help?

I'd be willing to help, but wouldn't you really need a hygrometer to accurately measure humidity? It can vary from the top of the hill to the bottom, not to mention when I get a boil going in my garage with the door partially cracked. Also, I think you may want to at least roughly categorize your data by pot configuration. A tall narrow pot will evaporate less wort than a short wide pot. In any case, pm sent...

El Pistolero said:

I don't think I have access to the internet...can I still help?

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Nice One. Atta Boy. I dont have internet access either.

I'm just looking for ballpark figures. Even if you live a ways away from the airport's weather observation, the RH won't vary that much. I'm just looking to get a rough idea.

Yes, kettle size does figure into the equation, but the variances in what we are talking will be minimal.

Basically I'm going to figure the table based on RH and 2 or 3 other figures.

Got your PMs.....I'll send out specifics later on, I'm brewing right now so I'm trying to figure out what the best way to do this will be.

JOHN51277 said:

Nice One. Atta Boy. I dont have internet access either.

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What's an "internet"?

I just got back from lunch. Has the intern et yet?

homebrewer_99 said:

I just got back from lunch. Has the intern et yet?

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Yes, externally.

ORRELSE said:

Scientifically, figuring evaporation rate is next to impossible--considering you need to enter so many variables in the formula--volume, wind speed, temperature, surface area, relative humidity, etc. However, I think if I get enough hard data I can come up with a table and extrapolate some data to get in the ballpark

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Shouldn't the intensity of the boil matter as well? I even think that this might be more important than RH and wind speed since the amount of heat that is absorbed by the boil stands in direct correlation to the amount of steam that is produced. Unfortunately this is hard to measure unless you use an electric immersion heater.

Kai said:

Shouldn't the intensity of the boil matter as well? I even think that this might be more important than RH and wind speed since the amount of heat that is absorbed by the boil stands in direct correlation to the amount of steam that is produced. Unfortunately this is hard to measure unless you use an electric immersion heater.

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That is why I keep saying it is nearly impossible to get a 100% accurate rate. There are literally 10-15 variables that would need to be considered, which would be one hell of a formula, and I'm no Einstein. I simply want a ballpark figure, and an empirical table is really the only way to do it. It will take about 10-20 batches to get enough data to put it together, IMHO.

But but but.....wouldn't the price of tea in China be a factor?

You know I'd help, but I keep crappy notes. Plus, I won't be brewing until after the new year.