Help diagnosing persistent off flavor

[labrusca]

Hey. So I’ve been all-grain brewing for several years now. Initially my batches (all ales save one lager) worked out well but in my more recent brews something I’m having a hard time identifying is creating the same off flavor from batch to batch (the past three batches or so).

I’ve changed my technique slightly over time (from bottle priming to kegging, from sanitizing with ethanol to starsan, using a secondary, fining with gelatin, etc.) but haven’t had any luck in clearing this up.

I would describe the flavor as rubbery, but I can’t see how my technique leaves any room for yeast autolysis even though that's my best guess for the cause of the problem. This flavor feels like it interacts with the hop bitterness and ethanol flavors. Also its strength is temperature dependent. I notice it more when the beer is cold and less when it is closer to cellar temp.

In batches where I was priming with sugar to carbonate in bottle the flavor was a lot stronger, especially if I added kraeusen prior to bottling. Interestingly I’ve noticed this taste in Yuengling’s lager too, but in that case it is orders of magnitude milder than what I am dealing with. Anyone know what this is or how to remedy it?

Thanks,
Labrusca

 

[kh54s10]

Autolysis is not likely something that you will encounter homebrewing unless you leave the beer on the yeast for many many months. I am suggesting over 6 months.

I found two possibilities:

Skunky
Tastes/Smells Like:
Aroma of skunk, musty, can be similar to burned rubber or cat musk
Possible Causes:
When hops are exposed to UV rays from sunlight or florescent lights, the alpha acids
breakdown and react with the hydrogen sulfide that the yeast make. This reaction
creates mercaptan. Mercaptan is the same chemical skunks secrete when they spray
which is why the smell of “light struck” beer is so similar to that of a skunk.
How to Avoid:
When fermenting beer in a clear container, always keep it out of any direct sunlight
or florescent lamps. A simple paper bag or towel wrapped around the carboy will help
to keep light out. All clear containers will let UV light in, however, brown bottles will
filter a majority of UV rays and help to keep your beer “skunkless” for longer. Avoid
green or clear bottles as these let almost all UV light in. Light-colored beers and beers
with a lot of hops are more prone to becoming skunky. Dark beers and beers that
utilize isomerized hop extracts are less susceptible to becoming light struck.

Chlorophenol
Tastes/Smells Like:
Plastic, Vinyl, Iodine Maybe seeming like rubber?
Possible Causes:
Using chlorinated tap water to brew or rinse equipment is the most common cause
for plastic-like or medicinal flavors. Medicinal flavors can also be the result of using
cleanser or sanitizer that is chlorine or iodine based. Some wild yeast will contribute
to a similar medicinal taste.
How to Avoid:
Don’t use chlorinated water to brew or to rinse equipment that will come into contact
with the beer. If chlorinated water must be used, use a water filter that removes
chlorine or boil the water for 15 minutes and then cool to room temperature to force
out any chlorine that may be present. Always use the recommended amount and
concentrations of sanitizers. Most sanitizers will not cause any off flavors when used
properly. When using bleach, use one-half ounce per gallon of water, let equipment
soak for 10 minutes and always rinse with sanitized (pre-boiled) water.

Keep thinking of things that have changed since you had a batch that did not have the flavor. Try changing back one thing at a time until it goes away.

Or maybe someone else can narrow it down.

 

[Gnomebrewer]

Rubbery taste can come from a few different things, the most obvious being contact with rubber (rubber washers etc.). It could also be a water issue (water changes seasonally, so it could be a summer issue with the water you're using - your water authority may be adding chloramine because of the increased temperature). Try using RO water.

The only time I've had a rubbery taste in my beer was from the hops - a dodgy packet of Nelson Sauvin. I found out that if the hop pellitiser burns the hops, they develop a rubbery taste.

 

[labrusca]

Hmm. I'm thinking it's probably the age of my hops pellets. I used fresh hops (as in last Fall's) in my current batch that I'm cold crashing atm. If the flavor is clean this time then that will clear this up. If not I'll have to look into either microscopy or streak plating to check for microbial contamination. Hopefully it's as simple as the age and freshness of the hops. I'll follow up with the results of the current batch later on.

 

[seatazzz]

If you've been brewing for several years you're obviously well versed in what can "ruin" a good beer. The only thing I can think of might be your equipment. A "rubbery" or "bandaidy" flavor could be resulting from something nasty setting up shop in a spigot or hard-to-reach area that needs dismantling and a full cleaning. If your hops have been stored properly (refrigerated) I don't see them causing this sort of issue, unless they were "bad" to begin with. Particularly pelleted hops, as they have a better shelf life than whole leaf. What's your process?

 

[SpeedYellow]

Hops is very unlikely.

Tell us about your water. What kind of filtering do you do? Might your water source have chloramines? What's the mineral content? Do you have an analysis?

 

[labrusca]

So, for my water I use RO and add minerals depending on what I'm brewing. My most recent brew that had this problem was a Koelsch. I'd have to grab my brew log to give you the exact mineral content, but it was a fairly soft and pilsner-like profile.

Seatazz, you asked about my procedure. My process starts with step infusion mashing in an insulated kettle. Mash-out is at 76* C. I lauter from an insulated, food-grade bucket through a copper manifold. Sparge water is kept at ~ 75*C and continues to SG 1.010. My boil is usually 90 minutes since I have had some DMS issues with 60min. Given that that's the situation hops go in after 30min of boil. With 15min remaining I add Irish moss.

The wort is chilled to 15* C in under 15min via immersion chiller. At this point I usually cover the brew kettle, strip the insulation, and place the wort in refrigeration around 5* C. The goal there is to maximize cold break, but also to allow to cold break to settle into a denser cake.

After that I siphon the chilled wort into the sterilized fermenter (food-grade bucket filled by boil-sterilized silicone hose). I pitch after the temperature has risen to around 13* C. I transfer to my secondary after eight to ten days of primary fermentation (sterile glass carboy, again by sterilized hose). At this point I cold crash to 2* C. After the beer has spent about three days at that temperature I add finings (pasteurized gelatin solution). I wait an additional three to four days before transferring to keg.

I do give sterilization a good bit of attention, but I’ll take it further on the next batch.

Labrusca

 

[SpeedYellow]

Your process seems reasonably good. I'd suggest two things: (1) make sure no trace sanitizer is finding its way to the beer (e.g. bleach sanitizer, starsan in airlock, etc.), and (2) avoid any plastics in case you have a leaching or sanitation problem. So maybe just batch sparge, thereby avoiding the sparge water bucket, and ferment in your glass.

Those are sort of hail mary's but that's just what I'd do.