Extreme Amount Of Water Loss In Boil

[Belgrave Brewer]

I've just started All Grain brewing. Everything is fine until I get to the boil. My research indicates that should account for an approximate 10% loss in the boil.

I've been going into the boil with a higher efficiency than expected out of the mash and lauter phases
(I'm using a 10 gallon cooler, mashing at 66C or 68C depending on style, then mash out with 77C water with sparge water.

I've worked out that I need a total of 25L in mash and sparging to achieve efficiency and have been getting a higher than expected efficiency Pre Boil.

25 liters through the grain comes to 21 liters into my pot for boiling. It is taking me nearly an hour to get to boiling (pot covered). Once at boil, I remove the lid and my 21 liters ends up being 12.5 liters after an hour. By the time I add 6.5 liters of water to the wort into the fermenter to achieve 19 Liters, I've lost a significant amount of OG as I've watered it down too much.

Basically, I'm losing a lot in the boil. I've got a 50 liter pot and am brewing 21 liters to achieve 19 liters. Has anyone else had this problem with similar equipment?

My pot may be too large for the batches I am doing (maybe I should double my batches) and the surface area is too large creating too much boil off creating much more than a 10% boil off rate.

Anyone had a similar experience. And if so, what can you suggest. I'd like to continue making 19L batches sometimes and making 38L batches on other recipes.

Regards,
BB

 

[kook]

How are you measuring your pre-boil volume? Are you sure that you've actually got 21 litres in the pot?

4 Litres doesn't seem like much loss for both grain absorption and the dead space in your mash tun.

 

[Adamt]

Something isn't right here.

Just for starters: Say if 8L boils off during the boil, and you add 8L of water at the end, you should have the same OG at the start of the boil and the finish. A negligible amount of fermentation fuel is actually evaporated in the boil, a majority is just steam (and other unwanted crap).

Also beware that SG at 60-80C is lower than SG at 20C, so all SG measurements should be taken at 20C or adjusted.

The boil off rate will only be affected by the amount of heat going through the wort. A smaller pot may reduce the amount of heat taken from the burner.

What kind of burner do you have? It seems very odd to take an hour to get to the boil and then acheive 30% boiloff in an hour. How vigorous is the boil once it gets there?

Have you done any efficiency calculations? What is the SG of your last runnings?

-Adam

 

[matti]

I am with kook on this one.
When you loose 8.5 l from pot to fermenter are you talking about loosing that just through evaporation?
How much do loose with the trub then....?

you can counter act this by putting flame on as you lauter straight in pot
this will reduce lagtime for boil.
Once you achieve a rolling boil adjust gas/temp just to maintain roll.
If you have a large evaporation area you can leave the lid on the first 20-30 min just watch out for boil overs.

I would also aim for a larger preboil quantity ones you're aware of evaporation rates.

matti

 

[Fingerlickin_B]

Dude, something is way off here!

You couldn't possibly be losing 8.5 litres to the boil...or could you? :blink:

Pretty much wondering here (as lightly implied in Kook's reply), are you measuring your pre-boil volume, or just guessing based on anticipated grain absorbtion/tun dead space/etc?

I did a couple last weekend to a not-as-usual volume and ended up with about a litre MORE than I wanted...I should have measured things first instead of simply trusting ProMash and what I thought was going on...measuring is the key I have learned

Not having a go, just wondering, as those figures look scary to me :huh:

PZ.

 

[vlbaby]

Dude, something is way off here!

You couldn't possibly be losing 8.5 litres to the boil...or could you? :blink:

Pretty much wondering here (as lightly implied in Kook's reply), are you measuring your pre-boil volume, or just guessing based on anticipated grain absorbtion/tun dead space/etc?

I did a couple last weekend to a not-as-usual volume and ended up with about a litre MORE than I wanted...I should have measured things first instead of simply trusting ProMash and what I thought was going on...measuring is the key I have learned

Not having a go, just wondering, as those figures look scary to me :huh:

PZ.

Losing 8.5L of your wort from a 21L batch in an hour seems very strange indeed. Thats a whopping 40% evaporation rate whilst only raising it to boiling temperature.!! What does it lose during an hour long boil??
I agree with fingerlickin, and think something else is to blame. Double check your measurement preboil and post boil.
Unless the bottom of your kettle was corrugated or something with nasa burner at full throttle,I don't think you could chew of 40% of your wort in raising it to the boil.

 

[Maxt]

Did an APA on Friday. Preboil volume was 31L.
Lost only 1-1.5L to trub. Ended up with 20L.
10L evaporated :blink:
I usually use 2 2400W elements to get to boil then turn one off. This time, as my efficiency has been a problem lately, and I have ended up with low OG, I used both elements for 90mins.

 

[Ross]

Whether you boil 40L or 20L the actual boiling loss will be the same. Therefore boiling 20L will give you % wise, double the loss of 40L. You will need to set the Beersmith loss % much higher for such a small boil.

Why are you boiling such a small amount when you have a 50L kettle? Efficiency will suffer drastically using such a small amount. You need to boil the full volume to get best efficieny out of your grains & hops.

Cheers Ross

 

[NRB]

For a "standard" batch of around 20-25L I've set the ProMash evaporation rate at 17%.

My preboil amounts are a lot larger than yours - a 24L batch started with 33L preboil. My personal take on the issue is that evaporation rate of %/hr is rubbish and it should be L/hr as a constant. Batch size is irrelevant when dealing with such small volumes and high powered gas burners.

You say 25L though grain means 21L into pot. For 5kg of grain, you're going to absorb a little over 5L of water. Then there's the tun loss itself, which depending on manifold/tun design could be several litres in itself. Then there's evaporation. Finally you have kettle losses to trub...

If you're only mashing/sparging with a total of 25L for a 19L batch, I'm not surprised you're coming up short. As I've said above, I use a LOT more water than 6L more than batch size. Case in point my last brew, 34L batch size, 80% efficiency, I started with 64L of water; there's 30L lost in total.

 

[oldbugman]

To correctly work out evaporation you need to take into account a few factors, the main being surface area or the liquid.

Other factors are

design of boiler(a keggle which is just a hole in the top will lose less from evaporation than a completely open pot, much the same as having the lid half on)

Temperature(vigor) of boil

Water Content of wort

Ambient Conditions - moisture content of air/RH and temp


An un calculated % figure is just a fudge factor

 

[Belgrave Brewer]

I'm using a water cooler as my Mash/Lautern Tun. I drain off into a plastic fermenter that has Liter measurements on it so I know how much wort I have pre-boil. Then it goes into the 50L pot.

I take an OG reading at this time as well letting the sample cool to 20C. My expected OG was supposed to be 1047 based on my recipe in Beer Alchemy (I'm on a Mac) and it came in at 1052, which makes me think my efficiency is better than 75%, which is what I have set up in Beer Alchemy. I have not taken a reading of the OG towards the end of the sprage water but it was running quite clear.

I took a temp reading before boil and the wort was at 53C by the time I got in onto the burner. I'm using a Turkey Burner with high pressure regulator and hose. I did notice the flames were not completely consistent on the pot, it needs another clean from the burn off of the paint from my first use a week ago. I was not going to stop boil to fix this and will do it before the next batch.

I'm using a 5 gallon glass carboy to ferment in and I am guessing how much is going in it based on the segment rings that go around the carboy. I then measure the amount of water I add to the carboy to get to the top ring which is the 19L mark.

I added 6.5 Liters to get to the 19L mark. That is how I'm measuring the loss to boil.

I'm boiling with the lid completely off and only a rolling boil. I do leave the break behind in the pot which I am guessing is 1/2 a liter, could be more.

I know something is not right, but I can only put it down to boil off as the wort fairy is not visiting and taking it for herself. Well, I did turn my back for a second.

So, I'm positive 21L is going into the Pot and am guessing and measuring the amount of water added to the fermenter but am pretty sure my figures are close to accurate.

It is such a big pot and I can only put it down to the amount of surface area of the wort giving it this high boil off. It does make sense that if I loose that much and add water back to it, I should get around the same OG, but my OG once diluted was 1038. Now, maybe I fudged this reading somehow.

I pitched the yeast around 5pm yesterday and checked it this morning and I had a big blowoff last night, yeast is loving this batch. I'll take another reading when I rack it off the trub and into secondary fermentation.

MaxT had 10L lost to boil? I'm not using elements, but that's a pretty serious loss as well.

I may need to go into the boil with more liquid and leave the lid 1/2 on the pot in order to cut my evaporation rate down. It's only my second AG and I'm still working out my equipment.

BB

 

[oldbugman]

Why not try sparging for a final volume of 25litres?

 

[Belgrave Brewer]

Yeah Ross, I do need to double my batches but I wanted to get a few brews under my belt working out my equipment then step up so I don't have more expensive failures if they happen.

I'm trying not to use my plastice fermenters anymore for fermenting that is. I'm using glass now and need to get a few more carboys to step up the amount I can do.

 

[Belgrave Brewer]

Why not try sparging for a final volume of 25litres?

That would definitely help. I'm just getting used to the equipment and based outcome on expected 10% loss which is not going to happen with my setup. I will need to try and cut down the loss to evaporation and increase sparging volume.

 

[NRB]

I take an OG reading at this time as well letting the sample cool to 20C. My expected OG was supposed to be 1047 based on my recipe in Beer Alchemy (I'm on a Mac) and it came in at 1052, which makes me think my efficiency is better than 75%, which is what I have set up in Beer Alchemy. I have not taken a reading of the OG towards the end of the sprage water but it was running quite clear.

Is this pre or post boil? In the above post made by me about my batches, my preboil volume was 46L at 1.047 - final batch of 34L at 1.063. I hit these numbers bang on.

Beer Alchemy should be able to give you an expected preboil gravity so you can calculate your efficiency. I find it hard to believe you're getting a 70% efficiency when your mash/sparge volumes are so low. How many litres per kg of grain are you doughing in at? Are you batch or fly sparging? Let's say you batch... If you dough in at 2.5L/kg you're going to add, say, 12.5L water, running off after grain absorption somewhere around 7L if there's no loss to tun. You are then sparging with another 12.5L to equal 25L in, or are you adding 22.5L to account for the absorption?

I'm using a 5 gallon glass carboy to ferment in and I am guessing how much is going in it based on the segment rings that go around the carboy. I then measure the amount of water I add to the carboy to get to the top ring which is the 19L mark.

Here's part of your problem - don't guess, measure. Once you know your system you'll be better able to 'guestimate' where you need to be.

I'm boiling with the lid completely off and only a rolling boil. I do leave the break behind in the pot which I am guessing is 1/2 a liter, could be more.

I suggest you actually measure this. Personally I leave behind 2-2.5L for an average wort, highly hopped beers leave more. Hop cones leave even more still.

It does make sense that if I loose that much and add water back to it, I should get around the same OG, but my OG once diluted was 1038. Now, maybe I fudged this reading somehow.

This goes back to my original suggestion of lower efficiency than you've set in your brewing software. To have a high extraction efficiency, you need to wash the grains thoroughly, something that doesn't seem to be being performed with such a low preboil volume.

MaxT had 10L lost to boil? I'm not using elements, but that's a pretty serious loss as well.

That's not unusual. From what I can gather looking at the figures from other people, 7-10L is considered 'normal' for a full wort boil. I boil for 90 mins so experience a higher evaporation than that.

It's only my second AG and I'm still working out my equipment.

That's why you need to measure every step to get the baseline numbers for your system.

Good luck!

 

[Belgrave Brewer]

Is this pre or post boil? In the above post made by me about my batches, my preboil volume was 46L at 1.047 - final batch of 34L at 1.063. I hit these numbers bang on.

Beer Alchemy should be able to give you an expected preboil gravity so you can calculate your efficiency. I find it hard to believe you're getting a 70% efficiency when your mash/sparge volumes are so low. How many litres per kg of grain are you doughing in at? Are you batch or fly sparging? Let's say you batch... If you dough in at 2.5L/kg you're going to add, say, 12.5L water, running off after grain absorption somewhere around 7L if there's no loss to tun. You are then sparging with another 12.5L to equal 25L in, or are you adding 22.5L to account for the absorption?

Here's part of your problem - don't guess, measure. Once you know your system you'll be better able to 'guestimate' where you need to be.

I suggest you actually measure this. Personally I leave behind 2-2.5L for an average wort, highly hopped beers leave more. Hop cones leave even more still.

This goes back to my original suggestion of lower efficiency than you've set in your brewing software. To have a high extraction efficiency, you need to wash the grains thoroughly, something that doesn't seem to be being performed with such a low preboil volume.



That's not unusual. From what I can gather looking at the figures from other people, 7-10L is considered 'normal' for a full wort boil. I boil for 90 mins so experience a higher evaporation than that.

That's why you need to measure every step to get the baseline numbers for your system.

Good luck!

It is Pre Boil Gravity
Expected: 1047
Actual: 1052

For this batch, I doughed in 15L and Fly sparged with 10L. I probably should have taken a reading a the end of the sparge water, but it was running clear after 10L through it. My reading of 1052, once it cooled to 20C, was higher than expected so my efficiency was not low. A total of 25L water through grain yielding 21L of wort. The grain bill was just under 5Kg. 15L was too much for the amount of grain, a mistake I made, but again, OG reading didn't make me think anything was wrong at this stage.

I did not think about measuring the amount I left behind in the pot. I know how big my carboy is and I measure the amount of water I put in it to get to the 19L mark on the carboy, so I know how much loss there was in the boil, not exactly, but pretty damn close. Yes, I can be more precise in my measurements and I think that is what everyone has been reinforcing here.

Is 10L not enough to Fly sparge with? If my actual PRE BOIL OG is higher than the expected Pre Boil OG with an efficiency of 75%, wouldn't that mean that my efficiency is higher?

Measure Everything...point taken.

Thanks,
BB

 

[NRB]

For this batch, I doughed in 15L and Fly sparged with 10L.

First of all let me say I'm far from an expert, but my understanding is that sparge water should be equal or more volume than the mash. I usually sparge (batch) with a LOT more water than I dough in with.

Is 10L not enough to Fly sparge with? If my actual PRE BOIL OG is higher than the expected Pre Boil OG with an efficiency of 75%, wouldn't that mean that my efficiency is higher?

See above.

The way I see it, of course your efficiency reads on paper greater than expected, but when you've collected less wort than expected it will be more concentrated. So in effect you're less efficient than otherwise appears. I believe you've left a lot of sugars behind in the tun. The thing that's doing my head in is that you say you had a preboil gravity of 1.052, you lost 6.5L of water during the boil so you added it back, but came out with 1.038? Something's gone wrong with your measurements as it simply can't happen, unless you've had a large boilover.

Let's run through my example again:
34L batch, target OG 1.063, 90min boil
7.5kg grain 80% efficiency.

Preboil
45.6L 1.047

Water needed:
18.79L dough in
7L boiling water added for mashout
so 26L into mash

Leaves behind 8.5L absorbed by grain so drain 17.5L if all can be drained, but I lose a little to tun deadspace. (not a problem if fly sparging)

I need 45.6L preboil, so I add 28L sparge volume.

Yes, my figures are rounded up and down etc, but you get the general idea. As I said, I use a LOT more water than you and I'm sitting at 80% efficiency.

What water volume pre boil did BA recommend? Does it have a "mash designer" or "water needed" calculator? I'm sorry I don't have a Mac so can't check it out myself. There's a few guys on the board who use the program, perhaps they can shed some light.

:beer:

 

[Belgrave Brewer]

Hi all, the mystery of the extreme boil off is solved thanks to a friend who is using the same glass carboys for fermenting. We were both under the impression they were 19 Liter carboys and they are actually 23 Liter carboys. So that difference of 4 Liters was part of what I was thinking was boil off.

Thanks for everyones help on this even though it was due to an ID10T error.

I've still got a few more kinks to work out with my new equipment and a bit more leaning to do, but this was the biggie I was struggling with.

My first 2 AG brews will be weak, but hopefully still very nice.

Time to bulk up the grain bill, more hops, more sparge water and get on with it! :super:

BB

 

[kook]

Can I recommend picking up a stainless steel ruler to measure the volume in the boiler pre/post boil?

 

[reVoxAHB]

Thanks for everyones help on this even though it was due to an ID10T error.

"All truths are easy to understand once they are discovered; the point is to discover them."

Galileo Galilei