Low gravity after boil... why ?

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Low gravity after boil... why ?

Unread postby Garage12 » Mon Jan 29, 2018 3:49 pm

Hello,

I just want to know if anyone here have the same problem than me... im using a 50L BM but I was having the same issue with my 20L

Im always close to the good pre boil gravity that Beersmith calculate ( so I guess my mash is ok ) but im always a few points off the target after the boil... the wort volume after the boil seems to be close to what Beersmith predict but my gravity is by example 1.056 instead on 1.061... so too much water volume... so the only way to fix this would be to add some DME or boil longer...

What parameter I need to modify to use less water ? Also Beersmith by example was telling me to sparge with 16L... Should I use the rule 1L / KG of grain ? I think that 6L less water should have bring me close to 1.061...

Im using Beersmith and my ''equipement profile'' specs seems to be quite good.

Thanks for your ideas.
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Re: Low gravity after boil... why ?

Unread postby grooves » Mon Jan 29, 2018 4:40 pm

I've been seeing the same problem - I'm guessing the boil-off value used is not correct in my case. I need to measure pre- and post- boil volumes more accurately.
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Re: Low gravity after boil... why ?

Unread postby Garage12 » Mon Jan 29, 2018 5:30 pm

grooves wrote:I've been seeing the same problem - I'm guessing the boil-off value used is not correct in my case. I need to measure pre- and post- boil volumes more accurately.


I measured the boiloff using only water I got 7.5L / hours on my 50L BM if I remember correctly but maybe I should put this value à little lower to help. That would help and make sense...
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Re: Low gravity after boil... why ?

Unread postby Onthebrew » Tue Jan 30, 2018 11:35 am

I’ve always had this issue. I just top up with less water. I’ll mash with 23 litres and I found if I only top up with between 4 or 5 I hit target OG( instead of 7 or 8 as I believe most do) My worry was that an under forming boil could have undesired consequences for the final brew.
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Re: Low gravity after boil... why ?

Unread postby Garage12 » Wed Jan 31, 2018 5:21 pm

Onthebrew wrote:I’ve always had this issue. I just top up with less water. I’ll mash with 23 litres and I found if I only top up with between 4 or 5 I hit target OG( instead of 7 or 8 as I believe most do) My worry was that an under forming boil could have undesired consequences for the final brew.


Thanks I guess I will lower my boiloff value in Beersmith... so if I want to finish with 45L in my fermentor Beersmith will probably tell me to put less water... or more grain... I will do a simulation by copying the same recipe and change some values...
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Re: Low gravity after boil... why ?

Unread postby mashy » Thu Feb 01, 2018 3:56 pm

Onthebrew wrote:Actaully noticed In James Mortons brew book, he follows mashys School of thought, and suggests topping up in FV for all his recipes, so you always hit your target OG
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Re: Low gravity after boil... why ?

Unread postby Onthebrew » Fri Feb 02, 2018 4:15 pm

that would help you hit target ( and cool down) but the real issue here is of a possible under performing boil - the boil isnt taking the gravity to where it should be- i am sure there are other ramifications of a poor boil.
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Re: Low gravity after boil... why ?

Unread postby mashy » Fri Feb 02, 2018 5:22 pm

I don't think it is. Yes a vigorous boil will of course release more water vapour. But a simmer is enough, you don't need to boil the beejeebers out of it.

Is it only the numbers making you question the boil.. Or something else?
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Re: Low gravity after boil... why ?

Unread postby Onthebrew » Fri Feb 02, 2018 10:22 pm

Just the numbers. I tend to use about 27, maybe 28 litres in total and am under the impression most use 30 plus to hit gravity.
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Re: Low gravity after boil... why ?

Unread postby mashy » Sat Feb 03, 2018 7:23 am

We all have different ways.
Different measures.
Boil at different alltitudes.
Use different numbers.
Use extractors or not.
Use hoods or not.

I really don't think you have a problem.

Does the beer taste good?
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Re: Low gravity after boil... why ?

Unread postby Onthebrew » Sat Feb 03, 2018 1:58 pm

Yes most of the time , decent enough. I just got used to using 23 plus 4, but this thread got me thinking about it again.

Bigger problems today though, feck knows what’s happening with today’s brew, the boil seems to be 30 per cent trub
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Re: Low gravity after boil... why ?

Unread postby mashy » Sat Feb 03, 2018 8:38 pm

I don't want to upset you, but IMO sparging it overrated on a BM too. (stands back to admire the fireworks :D )
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Re: Low gravity after boil... why ?

Unread postby Mashman » Sun Feb 04, 2018 12:19 pm

No fireworks here. 50+ brews on the BM, i think I sparged on the first two......

To much of a faff
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Re: Low gravity after boil... why ?

Unread postby Onthebrew » Sun Feb 04, 2018 1:14 pm

I’ve never sparged either.
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Re: Low gravity after boil... why ?

Unread postby Garage12 » Wed Feb 07, 2018 2:50 pm

Thanks all. I think I will stop sparging for a while and adjust the gravity at the end of the boil... or sparge with about 8L maximum on my 50L BM
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