Couple questions on odd tastes (Bannana esters/sedimenty/yeasty)

[bscarl88]

We've actually brewed about 12 beers, and mostly all of them have had this odd after taste that we would describe as sedimenty/yeasty/bananna esters taste and we're trying to figure out how to fix this.

Stuff we've run into:

• We haven't ever tried a yeast starter, and we were told that maybe our yeast doesn't have the count or time to cleanup after itself.
  
• fermenting around 70-72 degrees
  
• Sometimes (but not all of the time) we've re-racked the beer before the yeast is done to preserve some of the sweetening sugars.
  
• We rerack ~4 gallons after around 10-14 days in the primary back into the 7.5 gallon glass carboy. I was told the amount of air during the secondary could be giving us bad flavors.
  
• There's a decent amount of bubbles from the star san in our bottles when we are bottling
  

We've had some good beers, but they could all be improved with removing this off flavor from our batches. Any help is appreciated!

 

[btbnl]

What yeast(s) are you using?

 

[bscarl88]

we've used pale ale dry and a few different white labs liquids, they all still have the same results

 

[Qhrumphf]

Underpitching amd fermenting warm leads to increased esters. As many yeasts produce isoamyl acetate (the banana ester) it's not surprising you'd get it.

If your room temp is 70-72 then you may be fermenting as high as 85. Fermentation creates heat. 5-10 degrees above ambient is pretty common. I've observed 15 above ambient. Point is, its the beer temp that matters.

Removing the beer from the yeast before its done fermenting is a bad plan in general.

Yeasty can come from rushing the process (yeast still in suspension), or if you're pouring the whole bottle including sediment or drinking from the bottle, our pouring several times, instead of one smooth pour from bottle to glass leaving bottle sediment behind.

 

[bscarl88]

Underpitching amd fermenting warm leads to increased esters. As many yeasts produce isoamyl acetate (the banana ester) it's not surprising you'd get it.

If your room temp is 70-72 then you may be fermenting as high as 85. Fermentation creates heat. 5-10 degrees above ambient is pretty common. I've observed 15 above ambient. Point is, its the beer temp that matters.

Removing the beer from the yeast before its done fermenting is a bad plan in general.

Yeasty can come from rushing the process (yeast still in suspension), or if you're pouring the whole bottle including sediment or drinking from the bottle, our pouring several times, instead of one smooth pour from bottle to glass leaving bottle sediment behind.

that room temperature bit is great info, I have no idea how to get it any cooler than that though without turning the thermostat too cold for the other residents to handle. If I ferment it in the basement, then when I bring it back upstairs to rerack, all the sediment will be loose during the travel up my devilish basement stairs

 

[Qhrumphf]

that room temperature bit is great info, I have no idea how to get it any cooler than that though without turning the thermostat too cold for the other residents to handle. If I ferment it in the basement, then when I bring it back upstairs to rerack, all the sediment will be loose during the travel up my devilish basement stairs

Put your fermenter in a big plastic tote bin and surround with water. Water will not only restrain the spike in temp from fermentation (essentially pinning fermentation at ambient temp), but using soda bottles or milk jugs of ice and you can adjust the temp down further. Hard to ferment a lager this way, but you can ferment down into the 50s with enough maintenance.

Other techniques too. Search the forum for "swamp coolers".

Deal with that, making starters, and get yourself an aeration setup and you'll be in good shape.

And ditch the secondary. You usually don't need it. Just give it extra time in the primary.

 

[PLOVE]

[*]We haven't ever tried a yeast starter, and we were told that maybe our yeast doesn't have the count or time to cleanup after itself.

For most ales over 1.045 a starter (or two vials of white lab) would help, especially if the vial is several weeks (months) old and viability is low. For most beers, you should expect krausen (foamy goodness) within 12-18 hours. If Krausen isn't reached for several days, you likely underpitched and your yeast are lag phase - building up numbers for a feast.

[*]fermenting around 70-72 degrees

Yikes! Sure you're not brewing a French Saison?? As other posters have noted, you need to measure the temp in the beer, not air temp. Also, most american ale yeast ferm best in the low to mid 60's.

[*]Sometimes (but not all of the time) we've re-racked the beer before the yeast is done to preserve some of the sweetening sugars.

This usually doesn't work incidentally. Unless you're using sorbate or sulfates to kill the yeast, there will usually still be some around in suspension. Doing this will likely lead to bottle bombs. If you really want more sweetness and you're not doing full mashes (i.e. just raise mash temp), consider adding nonfermetables or performing a partial mash.

[*]We rerack ~4 gallons after around 10-14 days in the primary back into the 7.5 gallon glass carboy. I was told the amount of air during the secondary could be giving us bad flavors.

If the beer is still fermenting this is probably ok. CO2 is heavier than O2 and will act like a protective blanket. If you must rack (lots of debate on this subject), I'd recommend flushing your carboy with CO2.

[*]There's a decent amount of bubbles from the star san in our bottles when we are bottling

No worries on this front. Star san is designed to be a no rinse sanitizer. I wouldn't recommend adding a lot of liquid to your beer, but it's basically just phosphoric acid in water to lower the pH.

Good luck!
Pete

 

[bscarl88]

Thanks for all the help gentleman!

I'm going to:

• do a yeast starter
• try to ferment in my cooler basement (by surrounding the carboy in cool water since my basement isn't that much cooler than the rest of the house)
• not pull out of fermentation too early
• ditch the secondary

and see how it goes!

 

[TheHopfather]

I would add one more thing to your list. Make sure you lower the wort temp to your desired fermentation temp before pitching the yeast. Pitching yeast into wort that is too hot can lead to some off flavors as well, not banana like you're getting now, more hot alcohol but still a good practice.

You can also add frozen water bottles to the water bath to help keep temps lower.

Good luck!