Off flavor question

[chrryghst]

Hello experts! Can you review my brew day process and tell me if I'm on the right track to preventing a certain off flavor from appearing my next batch?

I've brewed three extract w/ specialty grain batches so far. They were all good, but all contained a certain flavor I wasn't fond of. After doing a lot of reading, I think it might be due to oxidation because it most closely matches the description of "wet cardboard."

One of the suggestions to prevent oxidation included avoid splashing hot wort. While I am very careful about avoiding splashing during racking and bottling, I tend to have a lot of splashing on brew day.

I recently learned that by pouring hot wort (> 80 F) through a strainer will oxidize it and give it the "wet cardboard" flavor. I typically cool my wort down to 95-100 F and add it to refrigerated bottled water for dilution to 5 gal. It does the trick to get the overall 5 gal down to about 75 F for pitching.

I also practice the late addition extract method and steep in a small quantity of water (3 qts/lb). After steeping for 30 minutes, I take an additional quart of hot water from a tea kettle and rinse the grain bag (this causes more splashing!). Then I pour the gallon of steeped water into my brew pot which contains 2 more gallons of heated water (more splashing!). I add about 1/5 of my extract, then I bring that 3 gallons of wort to a boil and proceed with the hop schedule, adding the remaining 4/5 of extract for the last 10-15 minutes of my boil.

For my next batch I will cool the wort all the way down to below 80 F before pouring it into the primary, and I will very gently rinse the grain bag without splashing.

Is anyone else familiar with this "wet cardboard" flavor?

 

[mcshaw16]

Others can correct me if I am wrong, but I have always been under the impression that aerating after cooling your wort and right before pitching the yeast was a good thing and necessary for the reproduction of the yeast in the early stage fermentation.

 

[GatoRailBrewery]

Aeration is key pre yeast pitch, what water are you using?? I was under the impression that oxidized beer happens post yeast pitch. How fresh is the extract?? Old extract makes beer dull flavored. For that matter old grain has the same effect. Don't think it was the air, as it's a common practice to shoot O2 through the wort to get optimum aeration.

 

[Bsquared]

Hot side aeration is not some thing really to be concerned about. Wet cardboard flavor is attributed to oxidation of fermented beer, and can be mostly attributed to improper handling during packaging.

Did you keg or bottle condition these beers? If you kegged is you transfer the beer with CO2 pressure, or take care to have purged the receiving keg with CO2? Was there lots of splashing around when you transfered?

If you bottled, I'm kinda at a loss other than if you had excessive head space or if during your transfer into the bottling bucket there was a bit of splashing that could have aerated your beer before going into the bottle.

The oxidation components in beer that make this "wet cardboard" flavor are easily formed and form quickly. And some people are more sensitive to this flavor than others. If you ever what to see how quickly it forms, just use a straw and blow some bubbles through a beer, (preferably a fairly neutral beer) you will taste wet cardboard soon after.

 

[chrryghst]

I've never really paid attention to how fresh the extract and grain are. I order from midwestsupplies.com and usually brew a few days after my stuff comes in. I bottle condition and I fill with a bottling wand until beer reaches the top of the bottle. When I pull the wand out it leaves about 1" of head space.

Water-- I live in an apartment which gets well water. I'm not sure, but I think the apartment complex has its own mini-treatment facility for the well water before it goes out to each building. And I have no idea about the specs. I typically use that water for the boil and then top off with bottled spring water (Ice Mountain). I was thinking about using distilled water for everything in my next batch.

So, now I'm starting to doubt it's oxidation. Wet cardboard was the closest I could find. I've had a very difficult time describing the off flavor. It is not astringenty, fruity, or buttery. It could be clove-like or maybe plasticy (phenols), but I just cant put my finger on it.

I've tried letting the beer sit for extra time in the primary as Revvy has said it allows the yeast to clean up the off flavors. I have also tried different yeast and different grains, but all still have that same undescribable flavor. I should also mention that the flavor is very aromatic too.

 

[Bk2X]

Have others had the same opinion as you?

 

[wailingguitar]

Are there any breweries near you? If so, take a bottle by and ask the brewer to taste it and give you an opinion.

 

[chrryghst]

Are there any breweries near you? If so, take a bottle by and ask the brewer to taste it and give you an opinion.

Yeah, there are plenty of breweries around here I could ask. I think I'll take it to a home brewing supply first though. I'm guess I'm just a little ashamed at my imperfect beer lol.

 

[mcshaw16]

Any chance it is a burnt flavor? Did you remove your brew kettle from the heat when you added your extract, if not could've scorched it.

 

[Yooper]

One thing that struck me right away is you're pitching your yeast at 75 degrees. I'd try much harder to cool your wort to 80 degrees, and THEN put it into the carboy (pouring then is great, and will help aerate) and try to pitch at 65 degrees or lower if you can.

What is your water like? Any chlorine or chloramines in it?

 

[TheWiz]

I'll go with Yoop's answer and also ask if you are fermenting in a closet. I was for a while and was also getting a plastic taste. It wasn't until I purchased a fridge to help with temp control that I got great beers. I was just fermenting at too high temps.

 

[chrryghst]

I'll go with Yoop's answer and also ask if you are fermenting in a closet. I was for a while and was also getting a plastic taste. It wasn't until I purchased a fridge to help with temp control that I got great beers. I was just fermenting at too high temps.

Yes, I am fermenting in a closet. I will admit that my temperature control isn't very good. I keep my thermostat below 70 but I don't control the sharp temp increase due to fermentation activity. I don't have space or money for a fridge, but I'll try the swamp cooler method next time. Also, I'll make sure to cool the wort to 65 before I pitch.

Thanks for the advice everyone! I've got a lot of new things to try to avoid that weird taste. Oh, I'm also going to make a yeast starter for the first time, just in case its an off flavor from under pitching.

 

[ChrisJPassarelli]

I'd recommend against distilled water! I'm pretty sure you need the nutrients and minerals in spring or other water for yeast prolification, whereas distilled doesn't give it anything to work with.

Besides that, it all sounds like good advice. I'm grappling with similar issues right now, with a persistent off flavor... best wishes.

 

[WhineinAlbany]

The water shouldn't matter since it's an extract brew. The extract itself should have nutrients from the water it was made from.