Ongoing off flavours - advice needed!

[enricosanchez]

Hi AHB , I'm on my 19th brew using my ever-expanding homemade 3 keggle HERMS setup. I have a problem that's been nagging me for the last 6 months.

For the last 5 brews I've been repeating this recipe to try and isolate the off flavours in my beer. The one flavour I've had trouble removing is a thick stewy sweet flavour. My FG always falls between 1.005 and 1.009 (checked with second hydrometer), so it's not sugar. I've been over pitching fresh yeast, and using a chest freezer fermentation chamber, so I think those points are covered. How To Brew suggests a vegetable flavour could be DMS, which leads me to think my burner may not be powerful enough. I'm currently using this type of burner, which eventually gets a rolling boil, but it usually takes 30-40 mins to boil. I boil for 60-90 mins with no lid, then cool quickly to ~30°C (86°F), aerate, then pitch at fermentation temp.

My base malt is Joe White Pilsner. Some brewers have suggested it produces more DMS than other grains but I haven't used anything else as a base malt so I don't have much to compare to.

According to http://www.melbournebrewers.org/images/stories/BrewWiz/key%20concepts%20in%20water%20treatment.pdf
"It soon becomes evident that Melbourne water is calcium deficient and requires calcium addition for all brewing. "

So I generally add 0.5g/l of calcium sulphate to the mash water. The last brew I added 0.8g/l. The beer still ended up with a very round taste. I don't want to say vegetable, but it's something like that. Thick round & sweet, not great to drink.

Can anyone suggest some changes before my next attempt?

 

[Screwtop]

Would you say kind of "honey like" sweet aroma????

Screwy

 

[SimoB]

What are your mash temps?

 

[verysupple]

Very pale crystal malt can be pretty sweet. Have you made other beers with the same 15 SRM crystal? If so, how did they turn out?

 

[manticle]

Describing the flavour better would help.

As Screwy says - is it honey like? Is it like green apple skins? Is it like creamed corn? Is it like butter or butterscotch?
Is the mouthfeel thick and maybe a bit slimy? is the flavour masking what you'd expect from hops and malt? Has it only been this recipe or all 19 or something in between?

How are you dispensing the beer? Kegs or bottles. If kegs, are the lines clean? Have you cleaned your fermenter and kettle taps properly (broken apart and thoroughly cleaned)?

 

[enricosanchez]

Thanks for all the replies, sorry I had some issues with my internet which delayed my reply.

@SimoB
Mash temps are usually either 62°C or 65°C, pretty consistent due to the HERMS

@verysupple
I've made a belgian tripel with exactly the same off flavour, no pale crystal malt in that one.

@Screwtop & manticle
More a honey like flavour, a little like vegetables. Thick smell on the nose and thick syrupy taste, If you know Birra Moretti well, it has that same kind of stew-like taste. Never eat creamed corn so I cant say.

Kegs and bottles, the flavour seems to be consistent throughout. I clean the keg lines every couple of weeks, I give the fermentors a good scrub with oxyclean. I don't usually take the kettle taps apart though. I always thought the heat from the boil would kill any nasties.

 

[micblair]

"thick, round sweet" all sound like under attenuated beers to me, but you've double checked your grav's. Aside from that, diacetyl lends a sweet and slick moutfeel for me - is it that?

 

[mxd]

where are you ?
look at joining a club or dropping off to some experienced brewers

are u a no chiller

what yeast

oxygen added

How long for fermentation

 

[stakka82]

Sounds like infection is a candidate, the wild yeast I have copped many times can be described like that... Are your beers flocking properly?

 

[enricosanchez]

The attenuation for the last four batches has been:
OG — FG = ATT
1.056 — 1.006 = 89.29%
1.053 — 1.007 = 86.79%
1.056 — 1.009 = 83.93%
1.049 — 1.005 = 89.80%

The recipe is supposed to be:

1.045 — 1.009 = 80.00%
But I prefer my beers a bit more boozy than 4.7%
The FG variation came from mash temp (I think). The OG variation came from boiling off more wort.


The beer really does taste dry but still has an off tasting sweetness, perhaps you're right about the diacetyl being the off flavour. I'll give the equipment an extra good scrub and pitch large this weekend. See how it goes.

I live in Richmond, Victoria.

Not sure about the infection thing, I have had a very thin white scum form on the top of 2 batches after 3 weeks on primary, but they didn't seem any more off flavoured than the other beers. I'm going to abandon my DMS theory and go the diacetyl paranoia for the next batch.

 

[Ducatiboy stu]

Very thin white scum after 3 weeks...mmmmm

Q. Why are you leaving it 3 weeks in the ferm.

The answer lies in the above queastion.

 

[enricosanchez]

I like to give it a chance to chill out for a while. 3 weeks in primary is just fine, right?

 

[mxd]

3 weeks should be ok, that's a lot of attenuation you have there.

If you visit G+G you could take a bottle and see if one of the guys there will assist.

Maybe buy a FWT and ferment that out to see if you have a fermentation issue or bugs in fermenter etc..

 

[SimoB]

3 weeks on a primary I find can sometimes leave a less clean flavor. The yeast cake can start to give off off flavors. Maybe brew and rack to a secondary after a week and age in that vessel for the extra 2 weeks. See what happens.

Sent from my HTC_PN071 using Tapatalk

 

[manticle]

I don't usually take the kettle taps apart though. I always thought the heat from the boil would kill any nasties.

The boil should kill the bacteria but if you have build up of gunk, the flavours can carry through. You wouldn't leave a beefstock pot uncleaned, just because it gets boiled would you?

White scum doesn't sound good.

Are these flavours present throughout fermentation, appearing in the keg or somewhere in between?

Honey sounds like 2-3 pentanedione (related to diacetyl but different), vegetables sounds like DMS, having them together along with white scum sounds like infection. Clean everything throroughly, get a new fermenter and hose and a fresh wort kit and ferment it out with dry yeast and no transfers.

 

[potof4x]

.....then cool quickly to ~30°C (86°F), ....
....I don't usually take the kettle taps apart though. I always thought the heat from the boil would kill any nasties.....

The kettle tap sounds a great place to start. It would be well worth dismantling it for a clean because the heat from a boil won't be enough to sterilse it completely.

 

[enricosanchez]

@manticle
The flavour generally becomes apparent a few weeks after bottling / kegging. Ok I'll give everything a scrub and try with a fresh work kit and yeast.

@potof4x
Fair enough, I'll pull everything apart for a wash before this weekend.

 

[enricosanchez]

By the way, thanks for all the input everyone. Really helpful!

 

[Screwtop]

Hmmm............ read what Prof Charlie Bamforth has to say re VDK's here http://www.brewersguardian.com/hop_bine_brewing_blogs/1579.html



Screwy