Soapy Taste.

[Little Rock Brewing]

My latest Proper Job AG brew had a distinct soapy taste when fermentation had finished.
I left it for another week, hoping the yeast would "tidy up".
But when I came to bottle it unfortunately it was still there.
Now after 4 weeks in the bottle I tried one and it's still present.
I'll leave it a while longer, don't need the bottles or space.

I can't find any reference to soapy taste in any of my books or online.
Any idea what may have caused it?

 

[Stu's Brews]

My latest Proper Job AG brew had a distinct soapy taste when fermentation had finished.
I left it for another week, hoping the yeast would "tidy up".
But when I came to bottle it unfortunately it was still there.
Now after 4 weeks in the bottle I tried one and it's still present.
I'll leave it a while longer, don't need the bottles or space.

I can't find any reference to soapy taste in any of my books or online.
Any idea what may have caused it?

Most likely culprits would be either that there was soap residue left in the fermenter before you added the wort or there has been autolysis occurring (break down of trub by yeast into fatty acids) from the beer sitting on the trub for too long after fermentation has been completed.

 

[Little Rock Brewing]

Well it's a no to soap residue for sure.
Maybe it was your second reason but the taste was there at 2 weeks into fermentation, hence leaving it longer.

 

[The Baron]

Could be the hops, what did you use?
Edit just looked at the hops in Proper Job and none give a soapy taste unless you have a bad batch or old hops which have been known to give soapiness at times.
Obvious culprit is the glass but I would think you have made sure that it was thoroughly cleaned

 

[Sadfield]

How long was it fermenting for? Do you carry a lot of trub into the FV? Do you know what pH the beer is?

Breakdown of trub into fatty acids (soaps are the salts of fatty acids) is one cause.

 

[Little Rock Brewing]

Could be the hops, what did you use?
Edit just looked at the hops in Proper Job and none give a soapy taste unless you have a bad batch or old hops which have been known to give soapiness at times.
Obvious culprit is the glass but I would think you have made sure that it was thoroughly cleaned

I'd have to check as it was an AG kit from the now defunct BrewUK. Got the kit just before they went under, in January.

 

[Little Rock Brewing]

How long was it fermenting for? Do you carry a lot of trub into the FV? Do you know what pH the beer is?

Breakdown of trub into fatty acids (soaps are the salts of fatty acids) is one cause.

It was in the fermenter for 3 weeks. FG sample and taste test at 2 weeks showed the soapy taste.
Very little trub in the FV as my procedure is to cool to about 40C then into containers overnight to settle and cool before pouring into the FV. Thereby leaving nearly all the trub behind.
I've never measured beer pH, just mash pH. I've got that pretty much sorted using 50% RO water.

 

[Little Rock Brewing]

One thought though.
The yeast was harvested from a previous batch of Proper Job and that one's yeast was cultured from a bottle of PJ.
So it's a second generation. Went off like a rocket though!

 

[Sadfield]

It could well be the trub within the yeast harvest that was the issue. Presuming that you harvested that way rather than top cropped. How long between batches?

 

[Little Rock Brewing]

Yes it was trub harvested and stored in the fridge for about 6 months.
I think you could well be right.

Will it go away in time?

 

[Sadfield]

I don't know, to be honest. Long, cold maturation might be the best thing to try. Any references I can find are more about prevention rather than removal.

 

[Little Rock Brewing]

Thanks for your help Sadfield.
I'll keep the beer in cold and dark and try it every now and again.
Also I think I'll give up harvesting yeast, especially as CML are so cheap.

 

[Stu's Brews]

Thanks for your help Sadfield.
I'll keep the beer in cold and dark and try it every now and again.
Also I think I'll give up harvesting yeast, especially as CML are so cheap.

If you wanted to keep harvesting yeast then it is a case of trying to make sure you have only yeast and no trub.

If you aren't dumping the trub before harvesting then I think the recommendation from the 'Yeast' book is to discard the first and last third of what you recover and keep the middle third (this assumes you are removing from the bottom of a conical fermenter or similar). The first third will be mostly trub and dead yeast cells, the last third are the less flocculant yeast cells that you probably don't want to propagate more of. The middle third should be the best quality yeast.

 

[The Baron]

I personally do not keep harvested yeast by the bottom of the FV method much more than a month but as you have said CML yeast is cheap enough, I only re-use if I have planned a brew in the next couple of weeks or use new if longer