Low SG before boil

[Poll]

Just in the middle of my 2nd BIAB.

German Lager

Batch size 50l

11.5kg Pilsener
Perle pellet
Halertau

My SG before boil is supposed to be 1047 but only managed 1032.

Mash was supposed to be 63 but I had it at 66 for 60 min. Any ideas why so low. Will it still be drinkeable. Any ideas solutions appreciated guys.

 

[n87]

provided you calculated the SG correctly... DME or a long boil.

 

[Poll]

How long u suggesting?

 

[n87]

no idea, the boil will get rid of the water, which will bring your SG up.
please note, you will end up with less wort than expected.

just remember, the hop additions are measured from the end of the boil.


im by no means an expert on this, ive only done a handful of AG brews... and havnt needed to raise the SG, ive mostly overshot.

 

[TimT]

The other thing is, of course the SG will depend on how much wort there is pre-boil - for instance, if you topped it up with a spare few litres then that will obviously affect the gravity. I wouldn't worry too much. Maybe when you've got it down to the final volume you're aiming for the gravity will be right. If not, make it a light beer, and improve on your process for next time. You'll still get beer in the end :chug:

 

[sponge]

How many L's do you have at 1.032?

How many L's did you use for mash and sparge?

 

[Poll]

Mashed at 40 l then sparged 4l then topped up to 61.6 for boil as per brewmate.

 

[indica86]

Hmm, I use 33 litres for 5 to 7kg grain. Why so little water for 11.5kg grain? I thought BIAB was full volume mash?

 

[Poll]

The guy from the brew shop said just put in 40l for the mash then top it up before you boil. Have I been misguided?

 

[n87]

i think the general idea is that you mash with as much water as will fit in your pot up to (final volume+boil off+absorption)L

this gives more water for the goodness to dissolve in. also more thermal mass and less headspace means less temp loss.

 

[Poll]

So would you suggest I take a reading at 60 min and if still a bit low keep boiling and check at say 30 min intervals after that till it becomes reasonable at say high 40's.

 

[Moad]

http://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/

That will tell you the volume you need to be to achieve your target gravity

 

[indica86]

The guy from the brew shop said just put in 40l for the mash then top it up before you boil. Have I been misguided?

Going by my limited experience I believe this goes against the philosophy of BIAB brewing.

 

[TimT]

i think the general idea is that you mash with as much water as will fit in your pot up to (final volume+boil off+absorption)L

this gives more water for the goodness to dissolve in. also more thermal mass and less headspace means less temp loss.


More risk of boiling over too. It all gets dissolved in the end anyway, dunnit? The boil creates a lot of currents, so sugars circulate around and get dissolved. I've also read that it's good to get a really vigorous boil going, since the wort will climb up the sides of the pot and tend to deposit unwanted gunk there, resulting in a clearer brew.

To fill up the pot or not fill up the pot.... oh dear, this could be another of those endless arguments....

 

[n87]

i think the general idea is that you mash with as much water as will fit in your pot up to (final volume+boil off+absorption)L

this gives more water for the goodness to dissolve in. also more thermal mass and less headspace means less temp loss.


More risk of boiling over too. It all gets dissolved in the end anyway, dunnit? The boil creates a lot of currents, so sugars circulate around and get dissolved. I've also read that it's good to get a really vigorous boil going, since the wort will climb up the sides of the pot and tend to deposit unwanted gunk there, resulting in a clearer brew.

To fill up the pot or not fill up the pot.... oh dear, this could be another of those endless arguments....

i was talking of the mash.
if OP is bringing the volume up to 61L pre boil, he would have the same issues regarding boil overs.

 

[TimT]

Oh yeah, sorry, misinterpreted.

 

[poggor]

did you correct your pre boil gravity reading for temperature?

 

[Poll]

Only new to this not quite sure what u mean. I finished the 60 min mash, sparged then topped to pre boil volume gave it a stir and took a reading. Didnt take much notice of what temp wort was.

 

[sponge]

Did you use a hydrometer or refractometer?

If using a hydrometer, you'll need to measure at ambient for an accurate reading.

 

[poggor]

for the same wort, density decreases with increased temperature. That is to say at 50c for instance, your SG will read lower than it actually is. most hydrometers are calibrated for 15 or 20c.
there are converters at www.brewheads.com (SG correction calculator)

you need a temperature which you probably didn't get. Can always take an OG reading at the end of boil and see where you are at, but harder to correct then (impossible without changing bitterness profile)