Topping Off and Off-Flavors

This is a long, long, long, long post, so bear with me if you have the staying power.

Did I mention this is a long post?

I’m posting this in General Techniques but it could arguably go into Brew Science.

I’m kind of going out on a limb here. This is only an idea that I am working through but it’s pretty interesting if it’s true. I have a science background and I've read a great deal about home brewing but I am certainly lacking a knowledge base about some of following ideas.

The background: I have brewed 12 batches of beer. The first was a kit with LME and specialty grains and the most recent was a BIAB all-grain, full boil batch. Most of those in between were BIAB partial boils with DME supplementing the grain bill. Except one... which was also a BIAB all-grain, full boil batch similar to my most recent. For the partial boils I used sterilized (boiled) tap water for topping off.

My beers have almost without exception tasted good at the time of the initial FG check in the primary. But, at varying points, most of them have developed off-flavors. I have now controlled my fermentation temperatures and have been using campden tablets in ALL water that I use. I have even been pre-boiling water with campden the day before brewday for top-off water. This has resulted in better beers... until they were bottled for a while. Then I got off flavors 2 or 3 or 4 weeks after bottling. My guess is that the incompletely fermented carbonating sugar and suspended yeast hide off-flavors until later into bottle conditioning.

More Recently: I entered a local homebrew competition and took second place with a beer that had been brewed almost 3 months earlier. It was the one batch that I had done all-grain and full boil. The two other beers I entered did not place. One was 3 months old and one was 6 weeks old (3 weeks of bottle conditioning) at the time of the competition. I can taste off-flavors in both. I’m not a BJCP judge but to me, it’s something bordering on phenolic or astringent.

This got me thinking about what I could have done better about the beers that did not place. Initially I was not even going down the road of off-flavors per se, really just trying to figure out why my beers were not hoppy enough. So, I recently began doing two separate boils on brewday (I only have 5 gallon pots) to enable a full volume boil without the need for topping off. I have read in a few places (including here) about a theory that IBUs max out at 100 per volume. So if you top-off, you will dilute that 100 IBUs and will never be able to achieve 100 IBUs. True or not, I have so far liked the hop flavor of my full boil beers.

However, what I have also noticed is that the beers I have made with full boils (2 weeks bottle conditioning maximum at the moment) are crystal clear. As in I can see detail through a 22 ounce bottle held up to the light. My older beers are clear, but nothing like these. And (although only 2-3 weeks in the bottle) the full-boil beers are carbonated and taste great.

Recently I also realized something about Star San. I have used Star San from the beginning including saving a spray bottle to help sanitize throughout my brewday and to use in the weeks to follow for checking FGs, etc. I had always known that Star San could last a while and that cloudy could mean it has gone “bad”. However, my spray bottles got cloudy shortly after making them. I still used the bottles with the thought that the cloudiness was something in my water reacting with the Star San causing an aesthetic issue but surmised the Star San was still good. After reading a few things on this site I decided to Brita filter my tap water for the Star San spray bottle. My spray bottle is now crystal clear after several days. Interesting.

Was I failing to properly sterilize my equipment and infecting every batch because of cloudy Star San? I doubt it. Once you put Star San in water, the water is also sterilized. So at worst I was using sterile water on my equipment. And my equipment is kept pretty clean to begin with. Infection is always possible. But I’m not buying it.

So I thought about why both Star San with filtered water and my full boil beers are crystal clear. Could there be a connection and could it affect flavor?

I’ve always known that my tap water has a high pH. It is about 8.8-8.9. From my understanding of pH, boiling the water will temporarily increase the pH and, when cooled down, maintain a pH close to, but slightly higher than the original. So, boiling in and of itself does not lower the pH. When you use a Brita, the pH typically drops below 7 to varying extents. So this might explain the Star San (which I believe likes a pH of 3.5 after it’s own affect on pH) even though some say that it is the softness of the water that affects clarity of Star San. This latter point may be true but that doesn’t explain why my beer is clear and (so far) tasting better.

My Theory: Topping off partial boil batches with water with a high pH results in off-flavors in beer.

This, of course, presumes that sparging and/or the boil corrects for tap water pH issues. From my somewhat limited knowledge, I can see how this would correct pH.

Alternative theories for an Occam’s razor explanation of the issues is that a change in water hardness or chlorine/chloramine levels could affect clarity and flavor. I have made Star San with water and campden tablets which results in cloudy Star San very quickly. So I don’t think this explains things unless I’m doing something wrong (1 tablet treats 20 gallons of water, cold or hot, almost immediately). As far as correction of hardness, I suppose this could be. But my local water profile is:

Hardness 50
Alkalinity 33
Calcium 20
Magnesium 4

With my water, I would not think hardness would explain things. But I’d love to hear other opinions.

Either way, if my theory is true, many brewers could care less. But everyone who does partial boils (hello fellow small apartment brewers) may benefit from this. Filtering or adding acid to top-off water may help any issues if you can’t do a full boil.

Again, I’d be really interested to hear opinions about this… I’m no expert and I’m fairly thick-skinned.

Hmmmmm. Do you have a full water report?

I think the issue here is the water. Have you ever tried doing one batch with totally reverse osmosis water from the store? I'd suggest that. Buying RO water for one batch, adding maybe 1 teaspoon of calcium chloride to the entire batch of water.

If that fixes the issue, you know it's the water.

I think it sounds like chloramines in the water, but you said you've been treating for that so I'm puzzled.

Thanks for reading through.

This is the most recent water report:

http://www.cambridgema.gov/CityOfCambridge_Content/documents/CWD_October_20101.pdf

I have thought about RO water or distilled water. I was planning this when I do my first pilsner for which I need soft water anyway. But I also want to see if the more recent beers develop any off-flavors.

Also, I've changed so many things since I first started. High temps created horrible esters and fusels and before the campden there were other off-flavors as well. But the off-flavors are different now. I don't think chloramine is the issue but you obviously have a lot more experience with this than I do.

The other odd thing is that the city of Cambridge has one water supply. And we have a great homebrew store in town. Tons of people brew here. And the brewstore has told me that Cambridge water is great for most beers as is.

The only thing I can think of is that I live in a highrise condo. Maybe the water for the building is somehow altered?

I know... I keep posting on my own thread.

Just an update.

I received my scorecards back from the contest I entered. There was no mention of off-flavors except that one of the 12 sheets (on the 3 entered beers) mentioned a yeasty flavor which I have never tasted. Maybe they got the dreaded last pour.

So I wonder if my off-flavor is only an off-flavor to me?

Either way, I am still intent on fixing it because I'm the one who drinks the majority of my beer.

I'm planning my next batch in a couple of weeks and I'm going to use RO or distilled with salt added, as suggested. We shall see...

Can you describe the off-flavor?

I also have the cloudy starsan water, I've only had two really noticeable off flavor which were metallic and oxidized. Searches on the web have identified that metallic happens and there's no definite reason. Both of these occurred in extract with grains partial boils. After those two I went to partial mash (with top off) and BIAB full boil and haven't noticed anything.

The oxidized flavor was like a wet cardboard flavor and it took about 3 months to develop in my pale ale. I'm sure there's a better descriptor for that off-flavor but that's the way I learned it for seafood sensory training.

Here's my water:
Calcium 56
Magnesium 22
Na 88
SO4 79
Cl 161
HCO3 134

Are your bottles stored away from light?

Its tough for me to describe the flavor. It is most noticable in the aftertaste. I think I would best describe it as astringent - like sucking on a teabag. Granted my description is biased and based on the stated "possible" off-flavor charts but it's the closest to accurate.

I keep my bottles in racks covered by thick towels to avoid light exposure. There is sunlight on the towels but I would think the towel is enough to avoid light effects.

Is the off-flav almost sour,like a lambic?

No. More astringent.

It's a painful ting and strange to me that others have not noticed it.

It isn't really wet carboard either. But along those lines, what would cause oxidation? Presumably at bottling? I carb by siphoning onto dissolved sugar in the bottling bucket. Is there anything else I should be careful about?

you can get oxidation anytime your splashing your hot wort or introducing oxygen into it after fermentation. I'm guessing mine occurred because I had a friend over who was vigorously stirring the boil.

I use a bottling wand and have noticed some air bubbles in it every once in awhile but I'm not sure if this can cause oxidation or not. Besides that I bottle just like you.

I'm not sure I buy stirring during the boil as an issue. A rolling boil "aerates itself".

There also seems to be debate about about hot wort aeration. But maybe that's what is happening to me despite me being a non-believer...

do you have a brew supply store near by?

maybe you can bring in a sample and see if they can give you any feedback

I do and I could.

But, I entered one of the beers into an MCAB qualifying competition. It got a 35 and there was no mention of off-flavors except (as I mentioned above) one mention of yeast.

I am doing an Imperial next week with distilled water and added salts appropriate for a 10-20 SRM beer. So we shall see.

I'm not sure an Imperial is the best test as it can overwhelm any off-flavors with malt and hops but my prior Imperials had the off-flavor...

ayoungrad said:

I'm not sure I buy stirring during the boil as an issue. A rolling boil "aerates itself".

There also seems to be debate about about hot wort aeration. But maybe that's what is happening to me despite me being a non-believer...

Click to expand...

doesnt a boil actually remove all/most of the disolved oxygen from the wort? Hence the need to areate prior to yeast addition?