Decoction Gone Wrong....

[Green Iguana]

I recently made up an oktoberfest brew using a double decoction....i tasted it about a week ago after it had been sitting in CC for 4 weeks at 2 C.... the brew had a slimey thickish mouthfeel and tasted weird so i considered it totally rooted so i ditched it.....( that really pissed me off since the mash/sparge/boil/decoctions took about 6 hours of work)...i want to know where i went wrong!

I am assuming that my problem was too much residual startches from incomplete conversion...i think this because i stuffed up the target temps in the mash.....would this be the cause...

 

[AndrewQLD]

post your recipe with the ACTUAL mash schedule that you used and we can have a look

 

[Green Iguana]

Here's the recipie + method.....

1 can coopers bavarian lager
500g extra light DME
1kg pilsner malt
1kg munich malt
14g hallertau @ 60 mins
14g hallertau @ 10mins
14g hallertau @ 0 mins
[ 1ltr starter of white labs " southern german lager" yeast ]

Used the following decoction method:

Strike temperature of 53C, stir well and rest for 20'
Stir and take 1/3 of the mash. (If you use a large proportion of unmalted grains you can take less of the mash and add water and dry crushed grains to make up 1/3 of the total volume). Heat to 72C, rest for 20' (malt) to 40' (malt+grains).
Bring to boil and boil for 15-30'
Add back to reach a temperature of 65-67C, rest 15-35'
Take 1/4 of the mash, boil for 15-30'
Add back to reach a temperature of 70-73C, rest until saccharification is complete (30'-1h).
No mash-out, start sparge immediately.

Fermented at 10 C for 2 weeks....diacetyl rest at 15 C for 3 days..then lager at 2C.

Here's what happemned to my mash:

strike was about 50 C.....all good.....first decoct of 1/3 i made quite thick....after adding back only reached 60 C...rested.....next decoct was very thick so i added a little water......after adding back to mash i only reached 62-3 C....not great i thought..so did another decoct + addeed boiling water...temp now stable at 65 C..let rest for 45 mins in hope that saccharification would b complete....first wort hopped about 30 % of the hallertau as well....

Like i said before..after lagering...the brew had a slimey gross mouthfeel and strange taste..i know what infections taste/smell/look like...this definatly wasn't infected....

 

[Green Iguana]

Any opinions from the info above...........

 

[AndrewQLD]

Sorry for the delay in reply but I have been off air for a little while.

Apart from the temp problems you had in the decoct your beer should really be fine. What was the final gravity before the lager phase??

If the brew finished with a high gravity then that slimey mouthfeel could be caused by the high amount of unfermentable dextrines.
Having said that don't fret, bottle or keg the beer and you should find that with the addition of the co2 from bottling your beer will not have such a slimy feel. It probably will be on the sweet side but still be drinkable.

Just as a side note (and this is my opinion only) I don't decoct mash at all as it really is not necessary with todays highly modified malts.

Andrew

 

[Green Iguana]

I was trying to get some biscutty/bready flavours that i love so much in german lagers.....ohh well

 

[bonk]

g.i

doing a decoct while not 100% needed as yes the malts are better then way back when and was used as people didn't have temp monitoring equipment and the grain was pretty crap. By doing the decoct the germans managed to get all the right temps and extract lots of beery goodness out of the grain.

now because our grains are better then before doesn't mean you can't do a decoct mash if you want to pull the maltiness levels up, i've done a triple decoct on a similar style and it tasted great nice and malty.

now if you can't be bothered doing a decoct mash, melandoin malt will provide a similar malty "profile"

so in a nut shell, nit sure where the slimely taste came from, maybe more lagering was needed??? and if you want to still do a decoct mash, go for it.

my $0.02 worth

 

[Green Iguana]

Cheers Bonk..... how do i use the melandoin malt and in what amounts?

 

[bonk]

not sure about it. i know Jayse has used it. also maybe the jovial one can provide some insight to the right amount.

as a guess i would say, less is best.

 

[warrenlw63]

You shouldn't really have ditched it.

Did you taste it straight from the secondary at 2c. You should at least let the sample warm up a little. Chances are the slimy mouthfeel you're talking about could just be a small amount of trub, yeast, hop debris from the bottom of the fermenter that's been hanging around the tap and gotten mixed up with your sample. More than a fair chance that the beer was probably OK. Did you disturb or move the fermenter before you took the sample?

Flat beer always tastes far more different at lower temps. Very real chance that you chucked out the baby with the bathwater.

Warren -

 

[AndrewQLD]

Bonk is right, melanoidal malt will mimic a decoction mash well, say about 5% of the grist, no more than 10%.

If you want a biscuity flavour try Amber malt you only need a very small quantity.

BeerSmith says:
Roasted specialty malt used in some English browns, milds and old ales to add color and a biscuit taste. Intense flavor - so limit use. Low diastatic power so must be mashed with well modified malts.

Andrew

 

[warrenlw63]

One more thing,

You didn't oversparge did you? This can be another cause.

Warren -

 

[Jovial_Monk]

Hmmmm a decoction increases extract (increases efficiency) as well as increasing color, maltiness and grainy flavors.

I do still tend to decoct most lagers and some ales. It does lengthen the brewday however.

Jovial Monk

 

[Green Iguana]

I batch sparged with 4 L......didn't disturb the cube before tasting...and yes the sample was pretty cold........oh well..live and u learn.....

 

[THE DRUNK ARAB]

I'm having a stab at a decoction tomorrow for my Oktoberfest. Hope I am not posting under this thread later h34r:

C&B
TDA