Can someone explain how...

a beer can look like this in the carboy



but look like this coming out of the keg...



just so you know...its a gose. 50/50 Pils and wheat

I am interested to see the comments on this thread.

Dirty keg? Dirty lines? Residue from last beer? All just guesses.

How is the taste? Any off flavors that you can notice, or flavors that differ greatly from earlier samples?

Food coloring

Well I did notice your brewery is in your bathroom so.......

It's all about optics and light refraction, and yeast flocculation. Carboy are notorious for things appearing different then they really are....


Obligatory science explanation done in small print:

Refraction
In addition to reflecting light, many surfaces also refract light: rather than bouncing off the surface, some of the incident ray travels through the surface, but at a new angle. We are able to see through glass and water because much of the light striking these substances is refracted and passes right through them.
Light passing from one substance into another will almost always reflect partially, so there is still an incident ray and a reflected ray, and they both have the same angle to the normal. However, there is also a third ray, the refracted ray, which lies in the same plane as the incident and reflected rays. The angle of the refracted ray will not be the same as the angle of the incident and reflected rays. As a result, objects that we see in a different medium—a straw in a glass of water, for instance—appear distorted because the light bends when it passes from one medium to another.

The phenomenon of refraction results from light traveling at different speeds in different media. The “speed of light” constant c is really the speed of light in a vacuum: when light passes through matter, it slows down. If light travels through a substance with velocity v, then that substance has an index of refraction of n = c/v. Because light always travels slower through matter than through a vacuum, v is always less than or equal to c, so . For transparent materials, typical values of n are quite low: = 1.0, = 1.3, and = 1.6. Because it is the presence of matter that slows down light, denser materials generally have higher indices of refraction.
A light ray passing from a less dense medium into a denser medium will be refracted toward the normal, and a light ray passing from a denser medium into a less dense medium will be refracted away from the normal. For example, water is denser than air, so the light traveling out of water toward our eyes is refracted away from the normal. When we look at a straw in a glass of water, we see the straw where it would be if the light had traveled in a straight line.

Given a ray traveling from a medium with index of refraction into a medium with index of refraction , Snell’s Law governs the relationship between the angle of incidence and the angle of refraction:

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Crap-all if I understand it all, but it looks cool!

The stuff in the glass does not look like pils and wheat. My yinzer batman senses tell me it should be really lite. Looks like a Porter almost. No clue.

The keg was spotless. Cleaned and sanitized pre kegging. The flavor is what it should be....tart, wheat, coriander and slightly salty. No off flavors. The beer literally looks purplish when pouring it down the drain.

As for the bathroom comment. The joys of 2 master baths. I've probably used that facility for its intended purpose maybe 5 times in the 5 years I've lived here.

This one just puzzles me. I've brewed and legged this beer before with no issues. The beer in it before was a Berliner Weisse so there wouldn't have been a dark beer to taint it anyway, even if it was dirty.

In the carboy there are lots of yeast cells in suspension. They scatter light back towards the eye making the beer appear light. If you shone a light through the carboy then the light would be absorbed and the beer would appear darker.

In the glass there are no (or many fewer) yeast to scatter light and so the beer appears darker.

Don't know what did it, but that's a huge swing in color. Thank you for sharing

There only one thing I can think of besides the light refraction issue. Oxidation will darken a beer, sometimes markedly. I've seen white wines turn brown, due to oxidation, and light colored beers turn sherry colored. That would have to be a darn severe oxidation though!

ajdelange said:

In the carboy there are lots of yeast cells in suspension. They scatter light back towards the eye making the beer appear light. If you shone a light through the carboy then the light would be absorbed and the beer would appear darker.

In the glass there are no (or many fewer) yeast to scatter light and so the beer appears darker.

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I've poured wheat beers I've made in that glass and in actuality, are much paler in color than the carboy because there's less liquid for light to travel through. This beer should look like a straw yellow color in the glass, instead it's like a purplish brown.

Yooper said:

There only one thing I can think of besides the light refraction issue. Oxidation will darken a beer, sometimes markedly. I've seen white wines turn brown, due to oxidation, and light colored beers turn sherry colored. That would have to be a darn severe oxidation though!

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I was thinking the same thing. I've seen brown chardonnays. This beer went right from carboy to keg and started carbing up. There's no sign of oxidation in the flavor either.

The carboy that I took a pic of is the split batch that's still aging (no boil Berliner). This is like some phenomenon that I can't imagine getting solved.

dirty_martini said:

I've poured wheat beers I've made in that glass and in actuality, are much paler in color than the carboy because there's less liquid for light to travel through. This beer should look like a straw yellow color in the glass, instead it's like a purplish brown.

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What you see depends on how much of the light that reaches your eye is transmitted and how much scattered. Obviously the appearance of the transmitted part depends on the amount of coloring material in the beer and the path per the Beer-Bougert-Lambert law (and the spectral composition of the entering light) whereas the scattered part depends on the number of yeast cells (and protein globs) in suspension and the direction of the impinging light (and its spectral composition). An interesting implication of the Lambert law is a shift towards red as the path lengthens. Wheat beers (mit Hefe trüben) really look their best when there is a balance of transmitted and scattered light. They almost seem to glow. A good photographer knows how to set that up. See, for example, the cover of Eric Warner's monograph in the AHA series.

Oxidation should not be a factor because no oxygen should have touched your beer.

I suppose refraction could be a factor if the Brewster angle were exceeded beyond which angle there in no transmission - all the light is reflected at the interface - but that would imply strange viewing - lighting angles.

Did you perhaps do a berry wheat in the past and forget the keg was still in there? Lines crossed? That's a weird one for sure!

Honestly I think you switched kegs.

Did you use sea salt or iodized salt?

Iodized salt can turn purple in the presence of acid or starch given a little bit of time. I had this happen to me with a batch of pickled eggs that I made once. I used iodized salt in my brine, and when it sat for a week or two, the contents reacted with the iodized salt to make everything in the jar purple! I guess that's why "pickling salt" is not iodized.

My guess is that you have a similar reaction happening in your beer from using iodized salt, which is reacting with the acid from your acidulated malt, or from unconverted starch in your beer. Check the packaging on your salt, and next time use pickling or sea salt for a Gose.

TB

It's the keg fairies

Tiber_Brew said:

Did you use sea salt or iodized salt?

Iodized salt can turn purple in the presence of acid or starch given a little bit of time. I had this happen to me with a batch of pickled eggs that I made once. I used iodized salt in my brine, and when it sat for a week or two, the contents reacted with the iodized salt to make everything in the jar purple! I guess that's why "pickling salt" is not iodized.

My guess is that you have a similar reaction happening in your beer from using iodized salt, which is reacting with the acid from your acidulated malt, or from unconverted starch in your beer. Check the packaging on your salt, and next time use pickling or sea salt for a Gose.

TB

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This makes complete sense. I wasn't familiar with the ingredients in a gose, so I hadn't thought about iodized salt. I was thinking that a reaction between starch and iodine would cause that kind of color, so maybe the OP had used iodophor to clean the keg and didn't rinse completely. But if iodized salt was used, I could definitely see the same thing happening.

Wow. I was all for "you got beer from the wrong tap" like you were pulling our collective leg but you have got to give it up to the HBT brew scientists

DregAddict said:

This makes complete sense. I wasn't familiar with the ingredients in a gose, so I hadn't thought about iodized salt. I was thinking that a reaction between starch and iodine would cause that kind of color, so maybe the OP had used iodophor to clean the keg and didn't rinse completely. But if iodized salt was used, I could definitely see the same thing happening.

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Agreed. I'm convinced that the OP used iodized salt, whether he knows it or not.

Clann said:

Wow. I was all for "you got beer from the wrong tap" like you were pulling our collective leg but you have got to give it up to the HBT brew scientists

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Definitely! Nice work Tiber!

IrregularPulse said:

Definitely! Nice work Tiber!

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Glad to help.

TB

DregAddict said:

This makes complete sense. I wasn't familiar with the ingredients in a gose, so I hadn't thought about iodized salt. I was thinking that a reaction between starch and iodine would cause that kind of color,

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It does?

First, in Switzerland where the dose in iodized salt is as heavy as it gets it's 20 ppb in the salt. At one gram of the salt per liter (I have no idea how much is used in this recipe, but 1 gram per liter strikes me as pretty salty) you'd be down another 3 orders of magnitude to 20 ppT. Even so, brewers are advised not to use iodized salt in their beers because iodine is poisonous to yeast apparently even at this level and below.

Second, if color were to form from a starch iodine reaction it would occur in the mash tun where we use iodine to test for the presence of unconverted starch. If the mash is adequately converted, the starch/iodine complex does not form and at most a faint reddish color is developed with an iodine concentration is more than a half dozen orders of magnitude greater than ppT. IOW if it were starch/iodine complex it would not wait to form until the fermenter where there is no starch to speak of.

The starch /iodine making purple doesn't make sense. Isn't that the point of the mash? to turn the starch to sugars for yeast? So what starch?

If you look carefully at the index finger in the picture of the glass, you can see the color coming through is red, not anything else. There has been some definite chemical change. - which points back to something like iodine and starch, again, where would that starch come from. While longer wavelengths (red) get through liquids better, the amount of a glass is insufficent for this to be a refraction issue.

What cleaners do you use? What is the recipe?

Native302 said:

It's the keg fairies

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dang, I thought I was going to be first to mention them. My vote is the keg fairies or the beer gnomes.

It can also happen with acid. That is how iodine was discovered (with acid).

Also, there very well could be small traces of starch in the beer from a less than 100% conversion, hence another possible explanation of why it happened gradually.

I don't know about you guys, but I think this is case closed.

TB

No it can't happen with acid if there isn't any iodine (ppT) and even if there is it can't be any acid. Courtois was working with sulfuric acid which is a powerful oxidizing agent under some conditions. Two things must be present for iodine color to develop from iodide: low pH and high redox state. Sulfuric acid and nitric acid provide both. Hydrochloric acid only the low pH.

Your lab assignment is to dissolve about a gram of potassium iodide in about 100 mL of water with one NaOH pellet (about 200 mg). This give a KI solution with high pH. Now add an oxidizing agent (I used H2O2). No color will be seen. Now add 28 Be HCl 0.1 ml at a time from a pipet. Where the blast of HCl hits the solution you will see the characteristic brown color of iodine but upon swirling it disappears again until such time as you have added enough to neutralize the NaOH pellet. At that time the color will persist and deepen the more acid you add. But it isn't the acid that is producing the iodine. It is the hydrogen peroxide. The acid just makes it possible for the H2O2 to work.

Part 2 is to make a strong solution of Mortons Iodized salt. Says right on the label that it's salt and potassium iodide. Repeat the steps above. Actually, you can skip the lye and just add the acid and hydrogen peroxide. You will not see any color because the amount of iodide in the salt is just too little.

So how about beer? It is acidic but it is in a reduced (you hope) state. I- cannot be oxidized to I2 (or I3-).

You can also repeat what Courtois did (be careful!!!!). Drop some concentrated sulfuric acid one drop at a time on a little KI and watch what happens. I2 vapor will be seen to rise and you will smell hydrogen sulfide proving that I- is able to reduce SO4-- all the way down to S-.

So I think the case is closed in the sense that we have proven it is not iodine and I think my scattering/transmission explanation is valid but I'd want to see the final beer in a cuvet in a spec and I'd want to see a sample of the fermenting beer centrifuged and in a cuvet in a spec before I definitely declared that explanation to be the one that pertains here.

Your assignment is to propose an alternative explanation and prove it.

The alternative explanation was proposed in #14. What I would need to have to prove that explanation is in #29.

iodophor left in keg.

Explain to me, then, how my pickling brine produced a deep purple when I used iodized salt. The same brine recipe with pickling (non-iodized) salt didn't. See #17.

I'm sorry, but we might have to agree to disagree here. No offense, sir.

TB

ajdelange said:

... and I think my scattering/transmission explanation is valid ..

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Not in this case. Sorry,too big of a diff. Look at that carboy. There isn't that much yeast in suspension (you can see most of it in the bottom if the carboy).

passedpawn said:

iodophor left in keg.

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I'm going with this one.

I'm sorry, it isn't iodine. I just took some corn starch and mixed with some idaphor solution - cool is this more purple blue

The color in the picture (look especially at his finger is) BEER more red, actaully I couldn't find 'burgandy' this is 'purple'. The color of the beer is burgandy - red wine color.

Iodine would be more indigo. Do the test yourself.

So what would cause burgandy color - clearly a 'redish' molecule like blueberry. OP stated no contamination, and doesn't give us his cleaning agents, or his ingredent list.

As to it being Beer-Bougert-Lambert law that can be tested by pouring into a hyrometer sleve - what the hydrometer comes in. If the color seems about the same - then in't isn't that (see http://en.wikipedia.org/wiki/Beer–Lambert_law - mostly prereq's which basically say that the law holds less effect with turbity and non parrell rays.

It is a chemical reaction, but not iodine. I'm beginning to wonder if the OP is pulling our leg and having us compare 2 different beers.

ACbrewer said:

I'm sorry, it isn't iodine. I just took some corn starch and mixed with some idaphor solution - cool is this more purple blue

The color in the picture (look especially at his finger is) BEER more red, actaully I couldn't find 'burgandy' this is 'purple'. The color of the beer is burgandy - red wine color.

Iodine would be more indigo. Do the test yourself.

So what would cause burgandy color - clearly a 'redish' molecule like blueberry. OP stated no contamination, and doesn't give us his cleaning agents, or his ingredent list.

As to it being Beer-Bougert-Lambert law that can be tested by pouring into a hyrometer sleve - what the hydrometer comes in. If the color seems about the same - then in't isn't that (see http://en.wikipedia.org/wiki/Beer–Lambert_law - mostly prereq's which basically say that the law holds less effect with turbity and non parrell rays.

It is a chemical reaction, but not iodine. I'm beginning to wonder if the OP is pulling our leg and having us compare 2 different beers.

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I thought it looked more purplish but I argue with my wife about colors all the time!

I also wonder too if he's gong to come back and say 'Just ****in with ya!'

jsguitar said:

I also wonder too if he's gong to come back and say 'Just ****in with ya!'

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maybe. OP is actively posting this evening in other threads. Why no comment in his own?

passedpawn said:

maybe. OP is actively posting this evening in other threads. Why no comment in his own?

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Good question. Easy enough to say 'Yeah, I did use iodophor', or 'Yeah, I forgot. I dropped four purple crayons in there. I was wondering what happened to those!'

Ah, I think I'm seeing the light. Heres a picture of one of my beers: http://www.pbase.com/image/136977075. And here's another picture of one of my beers (you don't have to hit the second link - just use the "Next" button.): http://www.pbase.com/agamid/image/136977072 It is now quite clear that while I had my back turned someone must have dumped iodine into the second beer because it is much darker in color. Right?

Not quite. Anyone who knows anything about color perception will immediately see what I have done. I took two pictures of the same glass of beer but in one case used only the ambient light and put the glass in front of a light background while in the other case I added some transmitted light and put the glass in front of a dark background. Not by design, but in support of the argument I have earlier advanced, by the time the second photo (the first one posted) was recorded some condensation had begun to form which scatters some of the impinging light enhancing the impression of lightness.

I recorded NEF's and then asked Photoshop to do Auto contrast adjustment i.e. what a cheap digital camera would do before cranking out a jpeg (which is what these images are). More to the point, I didn't "Photoshop" the pictures to make my point (which, of course I could have done). I only allowed it to do what a consumer camera would have done.

The bottom line is that what one sees and what a camera records depend very much on lighting, background source light color temperature and gamma in the camera.

With this evidence plus the chemical evidence presented in an earlier post readers should be able to conclude on their own that the cause of the phenomenon we see in the OP's original photographs are probably due to the color perception issues I illustrate here and mentioned in earlier posts. Theories involving iodine, iodophor, keg fairies and Barack Obama are, while entertaining, not likely to have relevance here. Common sense does play an important role in brewing science.

Now does this prove anything? Not really. The strangely silent, at this point, OP may have poured grape concentrate into the beer in the glass photo and may be laughing himself silly over this thread. I really don't know. I wasn't there. Nor do I feel obliged to speculate as to why someone might have gotten purple in a pickling operation. We're talking about beer here. Nonetheless an explanation could be that the pickling solution was in a oxidized state (as opposed to beer's reduced state) so that when iodine was added with the iodized salt it got oxidized but the chemical experiments show that iodized salt does not contain enough iodine to produce color and iodine (I3-) in solution isn't purple - it's orange - reddish - brown. Again, I don't know. I wasn't there.

passedpawn said:

maybe. OP is actively posting this evening in other threads. Why no comment in his own?

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Because I couldn't post any proof. I was posting from my iPhone app. I am going to take a pic of the beer next to the carboy so everyone can see it's not some refraction of light or other stretch.

I swear that it's the same essential beer. I mashed enough for 6 gallons and split it into 2 batches. One no boil Berliner Weisse, one gose that I boiled for 15 mins. Just enough to add a little hops as well as the coriander and salt. The Berliner is what's still in the carboy. The gose had reached the level of tartness I wanted so I kegged it. The Berliner is still aging.

As for cleaning and sanitizing, I use oxyclean and iodophor. I've been using it for years without ever having this issue.