Poll: What's Your Evaporation Rate?

[ozpowell]

Surprisingly, I haven't managed to find a previous poll on this topic. I consider mine to be quite high (around the 20% mark), that's why I'm interested....

 

[NickB]

Mines pretty high as well. In 90 mins I boil down from 37L to around 25-26L in the kettle. I voted 20%+. But hey, it works for me! Vigorous boil in a 50L SS 'vessel'.

Cheers

 

[AndrewQLD]

I can't reply to your poll because I don't know what my % loss is.

I do however know that I lose 6 lt per hour regardless of the size of my boil volume.

But I don't really think we need to go there :lol:

Andrew

 

[Cortez The Killer]

I've set promash to 3L per hour

I don't find that a % is consistent with changes in volume

There was a thread on point and I think that it was resolved (or argued anyway) that litres per hour was more pertitent

Cheers

 

[Julez]

Mines pretty high as well. In 90 mins I boil down from 37L to around 25-26L in the kettle. I voted 20%+. But hey, it works for me! Vigorous boil in a 50L SS 'vessel'.

Cheers

I reckon for the purposes of the poll, the measurement should be standardised!! The % loss is the hourly loss in relation to the vessel size, not the qty of wort in it.

e.g. lose 5L in one hour, kettle is 50L = 10% evap.

This is a consistent (not diminishing) rate of loss that applies almost irrespective of wort volume.

In the case of Nickb, your rate of loss would be 8L/hr (12L/90mins), divided by kettle volume of 50L = 16%.

It took me a while to figure this out a few months back, as I totally bollocksed up my anticipated evap qty in my first AG by misinterpreting this rate calculation .

 

[Julez]

I've set promash to 3L per hour

I don't find that a % is consistent with changes in volume

There was a thread on point and I think that it was resolved (or argued anyway) that litres per hour was more pertitent

Cheers

Hey Cortez, the % rate is consistent in relation to the vessel size. So long as you work it out as a % of vessel size, not wort volume, as I explain in my previous post. But yeah different way of saying same thing.

Cheers :icon_cheers:

 

[Guest Lurker]

But I don't really think we need to go there :lol:

Andrew

Anyone feeling dizzy?

 

[Prawned]

I think mine is around 8lts/hour.. i like watching it boil like crazy not so great on the gas bill though

 

[peas_and_corn]

A little over 20%- Promash is normally set to 20% but I think I should boost it by a bit, probably only a couple %.

 

[Stuster]

I can't reply to your poll because I don't know what my % loss is.

I do however know that I lose 6 lt per hour regardless of the size of my boil volume.

But I don't really think we need to go there :lol:

Andrew

+1 to all this. Evaporation between 5L and 7L depending on how hard I boil, but usually 6L.

 

[the_fuzz]

go from 27L down to 23L in 60mins - I use a lid with small holes in it to help prevent boil overs

 

[Tony M]

I can't reply to your poll because I don't know what my % loss is.

I do however know that I lose 6 lt per hour regardless of the size of my boil volume.

But I don't really think we need to go there :lol:

Andrew

Lets go there. The evap rate can only be measured in litres/hr. When you know this, you add this to your finish volume, so if you evap 6 litres and want 24 to run to the fermenter, you start with 30 litres. If you want 48 litres, you start with 44 litres. If you start thinking in percentages, you'll end up in trouble.

 

[Julez]

Lets go there. The evap rate can only be measured in litres/hr. When you know this, you add this to your finish volume, so if you evap 6 litres and want 24 to run to the fermenter, you start with 30 litres. If you want 48 litres, you start with 44 litres. If you start thinking in percentages, you'll end up in trouble.

This can be expressed as a percentage of the kettle volume, but there really isn't any point to it. As you say, it's always a consistent number of L/hr. However, your kettle size doesn't change during a boil either, so if you always lose 5L and your kettle is 50L capacity, you always lose 10%/hr, irrespective of batch size.

People keep making the mistake of calculating the evap in L as a % of the wort volume, rather than their kettle volume, but that is totally unreliable as it will continue to vary with batch size.

So for the purposes of this thread, if you really want to compare your losses to someone else's, the only way to do it is to compare your % loss, calculated as evap in L, divided by kettle volume - NOT wort volume!!

For the purposes of your own water calcs though, the L/hr figure is far more practical to work with.

'nuff said

 

[newguy]

I lose 8.7l in 90 minutes. All of my boils are at least 90 minutes, sometimes more for styles that require it. This is for double batches - I end up with ~43l in the kettle when I'm done, and usually leave behind about 1l with the trub. That's about 17% for 1.5 hours, or about 11% in 60 min, assuming things are linear, but they're not. Close enough.

 

[TasChris]

I lose 7l/hr out of a keg shaped kettle using a NASA burner.
This result is fairly consistent.
The hole in the kettle is fairly large and I don't cover it at all

Chris

 

[RobW]

+1 to all this. Evaporation between 5L and 7L depending on how hard I boil, but usually 6L.

+2

 

[Cracka]

+2

+3 But don't tell anyone I've only done one AG h34r:

 

[Adzmax]

I think mines about 15%. I reckon the evap rate of water might be different to wort though and I also think the volume of water migth play part so I need to do some more reasearch here

What I need to do is buy some dowel, fill my boiler 1ltr at a time and put markings on it so I can just use the dip stick to measure. I have the wood, just waiting for the next brew day then I can work it out more acuratly.

 

[Pumpy]

Interesting Poll I am in the 13% band which appears to be average

Pumpy

 

[Thirsty Boy]

I aim for 15% per hour of my pre-boil volume and will manipulate my system to make sure that I get it.

I'd love to go there again ... but it been done so many times in the last year or two that I think we are all over it