Decoction Help....

[Green Iguana]

how important is it to hit the 65-67 C range when adding back the first decoction....i only got to 57 C and just rested it for 30 mins....doing the second decoct in 10 mins....looks like i'll get nowhere near the 70-72 C range after adding it back.....this is only a 2 kg partial mash so i don't have the volume....

Am i still ok without getting the correct temps? will a 30 min rest at the end ensure
saccharification is complete even if its at a lower temp?....



cheers

 

[Jovial_Monk]

Hmmmm most books recommend sach temp of 64-70C

57C is really protein rest temp, not anywhere near the optimum temp of betamylase (60-65C) and that can't work untll alpha amylase, optimum temp 70C, has chopped some starch molecules into dextrines

Reckon you should have added some boiling water

Should also have done an iodine test.


Jovial Monk

 

[Green Iguana]

pulled 2 more decoctions after the 2nd one to get the mash to 65 C ....rested for 40 mins to hopefully ensure conversion.......

i did add boiling water but the esky was a 50L barstard....too much head space ( yes i did pre warm it ) for a 6 L mash.....live and u learn...its a heap of work to do decoctions...learn't that this arvo too...

but the smell coming off the brew pot is wicked....malty halleratu...

excellent........

 

[Jovial_Monk]

When you say "pulled two more decoctions" exactly what did you do?

Three decoctions (3 boils of 1/3 of the mash) would have killed all the enzymes!

Yup, decoctions lengthen the brewday but increase maltiness and bready-graininess and improve extract. would stick to two though: One to bring mash from protein rest to sach rest and the other to mash out when you want t kil the enzymes anyway

Jovial Monk

 

[Hoops]

JM

there would still be 30% of the enzymes alive wouldn't there?
If this was the case how would it affect the mash? would the time need to be dramatically increased?

Hoops

 

[Jovial_Monk]

ummmm 3 x 30%=90%


any third decoction would be to mash out

I am pissed on a really great red! Yes!


Jovial Monk

 

[Hoops]

JM

not to sure how decoction works - take third, heat and add back to mash tun?
If this is the case then..
1st decoction = 2/3 of enzymes remain
2nd decoction = 2/3 of 2/3 of enzymes = 4/9
3rd decoction = 2/3 of 4/9 of enzymes = 8/27 = 29% of enzymes

Hoops

 

[Green Iguana]

The first decoction i took was 1/3 of the mash...all the others were 1/4.

remember that the enzymes are mostly in the liquid part of a mash....the decoctions i pulled only just had enough liquid to prevent scortching..they were mostly grain.....after the two necessery decocts i had to do two more to get the final resting temp up to 65 C....i realised that taking too much liquid would kill all the enzymes so they were super thick.....i just wanted to ensure most of the startch was converted.there was no mash out....next time i might just do one decoct..this would make hitting target temps easy as....

cheers

 

[Jovial_Monk]

A decoction involves boiling the wort/grain mix

Love Hoops math lesson

But still, would kill an awful lot of the enzymes.

GI, if I was doing thick dedocts like yours, I would have added water to the grains b4 boiling, each decoct would then have added more heat to the main mash


Jovial Monk

 

[Green Iguana]

Thats a great idea JM .... cheers ... why didn't i think of that?