Biab not expected attenuation

[teno46]

Gday all, long time listner first time caller... (10monthsish)
Peface:
Biab, not expected attenuation
3kg pils malt
2kg munich malt

20L @ 70°c strike
68°c for 60min
Remove grain bag put into 10L @ 80°c for 10mins.
Combine wort
Boil 60min.

20g hellertau @ 60min
20g hellertau @ 10min
20g hellertau @ 0min
Expectexd SG: 1.048

SAFLAGER W34/70 @ 10°c for 10days
Gravity @ 1.020 (expecting FG~1.011)
Temp raised to 14°c
Gravity didn't change after 3 days.
Transfered to secondary, yeast cake to jars.

Problem:
After tranfering to secondary for cold crash
Yeast jars sat for 2hours, contents started to separate.
After opening lids got a positive pressure pop and contents appeared to mix itself.

I decided to repitch the yeast jars at the slightly warmer temp 20°c and put back in the fridge at 15°c.



Did i make the right decision? Should i have increased temps before transfering to secondary?

Thanks for any input, still green at this.

Brett

 

[Rocker1986]

I would suggest your mash temp is part of the reason for it. 1.020 still sounds too high though.

Personally I don't bother transferring to secondaries. It's a waste of time in my opinion (in almost all cases anyway). I would have raised the temp in the primary and probably gone higher than 14, probably around 17-18. Leave it at this temp for another week and see what it does.

 

[mxd]

I think 68 may be a tad to high for a pils, but should be lower

at the 10 days I would have increased the temp to 14 to 16 and left it alone for a week.

What you have done is fine. It should turn out AOK.

 

[Reman]

Also give the fermenter a bit of a swirl to try and bring a good amount of yeast back into suspension.

 

[Bribie G]

At 68 degrees you would have ended up with a fairly dextrinous wort that ferments out quickly. That explains the fairly quick 3 day fermentation.
For a Pilsner I'd go 62 degrees for 40 mins, 72 degrees for 40 mins then mashout at 78 degrees for ten minutes then drain.

Also, how accurate is your thermometer? Maybe you were mashing at 70 degrees. On the odd occasion that I do a UK mild I mash at around 70 and end up with a FG of around 1020.

 

[teno46]

Thanks for the replies.

I checked the gravity of one of the jars sitting on te bench for a few days. It had dropped to 1.1010.
I checked the gravity of the beer in the fermenter and it had started to drop also.

Between higher temps and pouring the yeast back on top may have kicked it off again.

Ill give it abuser l another couple days then cold crash.


I was following a recipe for the 68°c. What temp would be more appropriate?
I tend to have about a 5° change during mash. Is that to much?

 

[teno46]

Thanks for the replies.

I checked the gravity of one of the jars sitting on the bench for a few days. It had dropped to 1.010.
I checked the gravity of the beer in the fermenter and it had started to drop also.

Between higher temps and pouring the yeast back on top may have kicked it off again.

Ill give it abuser l another couple days then cold crash.


I was following a recipe for the 68°c. What temp would be more appropriate?
I tend to have about a 5° change during mash. Is that to much? Ie; strike temp about 71. After adding grains about 68. Drops to 63, i heat back up to 70.

 

[Rocker1986]

You should do something about that temp dropping like that. It shouldn't be losing heat. Or at least not that much. For a pilsner I'd probably mash it somewhere between 64 and 66 for 90 minutes.

 

[Bribie G]

Do you use a pot or an urn? When you hit mash temperature, if you lag the tun with a cheap doonah (I use the $12 one from Big W - they actually lag far better than the heavier expensive styles) and an occy strap if you wish, you shouldn't lose more than a degree and a half over 90 minutes.

Also grab some bubble wrap and do a circle the same diameter as your tun and float that on top of the mash then put lid on.

 

[teno46]

Im using a 50L stainless pot, with a large gas burner.

My latest brew (after the pilsner) i wrapped it in sticky backed foam. Had an effect, not amazing, may not last another brew.

I have lid on the pot, lift it every 15mins to move the grain bag, stir water.



Ill see if i can sort out the temp issue, then try the same brew again.

 

[Reman]

I cover mine with foil on top (shiny side down), then the lid and wrap a few towels over and around the pot and I get about a 1.5c drop in temp over 60 mins. I tend to mash in slightly above target temp and it drops to slightly below. I don't bother stirring as I think opening it all up just drops the temp too much.

 

[yankinoz]

Try calibrating your thermometer even if you've done it before. If it reads two degrees too low, you would have got sugars 34/70 won't ferment.

If the thermometer is fine, then fermentation conditions, not BIAB, are the likely explanation. Try the above remedies.

I notice your sparge temp. Why 80, on the border for extracting astringency? Wlith BIAB + sparge, because the grain in the bag easily drains, you do not need to thin the grain with a warm sparge. There was a thread on this a while back; I go less than 70 and some use sparge water at ambient. Keep the pH on the low side.

A lower mash temp would give you drier beer if that's what you want. Reportedly most German brewers today use a Hochkurz mash, i.e., mash at about 62 for, say, 45 minutes, then raise with hot water to 70. you get dry beer and very high mash efficiency. Some still decoct.

 

[teno46]

I follwed this recipe,slightly changed it the second time to see what happened.
http://brewerschoice.com.au/biab-bavarian-lager/