Missing target volume

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Mics100

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I've just brewed a batch of bitter and my post boil volume is 17L. I'm quite frustrated as I'm aiming for 20-22L post-boil and I've been missing for the last few batches.

I even over sparged today to 27L as my pre-boil volume thinking that I'd have an excess after a 1hr boil.

Is it simply that my evaporation rate should be changed in BrewSmith to 10L/hr. That seems like a lot. I've got a default setting of 1.89L/hr at the moment.

I'm going from a 55L esky mash tun into a 50L kettle. My new burner (1st use) is pretty hot and i had to watch the thing for the whole boil as the wind was pretty crazy and caused some heat fluctuations.

I'm yet to measure my OG as I use a no-chill method. I'm hoping its up in the 1.060+ range to allow for greater evap.

Any suggestions?
 
1.8 seems low. I aim for about 10L total loss (so evap and trub) over a standard 90 mins.

You need to input actual figures into software if you expect realistic predictions.
 
manticle said:
1.8 seems low. I aim for about 10L total loss (so evap and trub) over a standard 90 mins.

You need to input actual figures into software if you expect realistic predictions.
And measure your actuals against these predictions, reinput if required
 
I tend to keep a lid 2/3 over the boil pot, means less heat required to keep a rolling boil going and slightly less evaporation.
 
Trying to lock down boil off rates with a burner is pretty hard if your burn rate from batch to batch is different. Answer is yet another valve :D, Use the needle valve that came with the burner to set the burn rate, and never touch it again. Place the new valve between the needle valve and the tank for the express purpose of shutoff.

Job done.
 
manticle said:
Once the boil starts, I'd recommend lwaving uncovered.
All good. Is there a technical reason to do this? A little condensation does fall back into the wort with the lid 2/3 on.

I make smaller batches 12.5L pre-boil leaves me with 10.5 post boil (small sizes while I'm learning, once I figure out how to make good beer I'll up the volume).
 
Why can't you just top up with boiling water to desired volume towards the end of the boil?
Maybe someone will enlighten me.
I always adjust my volumes to get the OG I'm chasing during the boil.
 
good4whatAlesU said:
All good. Is there a technical reason to do this? A little condensation does fall back into the wort with the lid 2/3 on.
I make smaller batches 12.5L pre-boil leaves me with 10.5 post boil (small sizes while I'm learning, once I figure out how to make good beer I'll up the volume).
Part of the reason for boiling is to allow unwanted volatile compounds to dissipate. One such compound is dms. DMS comes from a precursor (SMM) which is naturally present in the wort. High levels of smm can be converted to dms during fermentation so boiling transforms smm to dms and evaporation removes the dms. DMS can make beer taste like creamed corn, tomato sauce, overboiled broccoli stems, etc, depending on level present.

You can float a small foil takeaway container to increase boil vigour yet still get effective evaporation. Or just increase the heat if possible.
 
manticle said:
Part of the reason for boiling is to allow unwanted volatile compounds to dissipate. One such compound is dms. DMS comes from a precursor (SMM) which is naturally present in the wort. High levels of smm can be converted to dms during fermentation so boiling transforms smm to dms and evaporation removes the dms. DMS can make beer taste like creamed corn, tomato sauce, overboiled broccoli stems, etc, depending on level present.
You can float a small foil takeaway container to increase boil vigour yet still get effective evaporation. Or just increase the heat if possible.
Good to know, thanks.

I am currently losing about 15% preboil volume but it looks like 30-40 % may be acceptable for a fully uncovered brew? Good to know, I may have to up the volumes a bit.
 
30-40 is very high.

I'd suggest 8-12 is an ok range. Too much above or below needs tweaking.

Uncover, reduce heat (or change boil vessel shape).


Don't forget losses to fermenter should account for everything - not just evaporation.
 
Looks like I had my burner set too high. The colour changed from gold to copper, which shouldn't happen, it's caramelised. Hopefully this doesn't affect the flavour too much.
I've made some adjustments and it should be okay now.

The wind was crazy yesterday and really played havoc with my kettle flame. I need to find a new spot to boil. :(
 
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