co2 solubility factors, I WANT MOUTHFEEL

[boss429]

I want to know why some beers go flat right away and some don't. When they go instantly flat (such in my beer) you get no mouth feel or watery texture.

I came to a conclusion that there are factors beyond ABV,pressure,temperature etc.. that affect the solubility of co2. (probably proteins? yeast?etc??)

I know this because on my home brew bubbles start in middle and take about 5 seconds to get to the head. Once the bubbles get to the head there is no CO2 in suspension anymore. On a micro unfiltered beer it takes about 2-3 seconds and feels about the same. On a filtered micro it takes about 1-2 seconds and the liquid beer when drank has nice carbed mouth feel.

Why is that?

 

[SakARow]

Do you bottle or do you keg? If you are kegging you might not even be carbing correctly. But who knows so I wont assume that. But temperature has a dramatic effect on CO2 in solution, as does the volume of CO2 in solution to begin with.

I think what you might be observing is the different carbonation levels. CO2 is incredibly small compared to a protein and proteins like to coagulate with eachother, which decreases entropy and in turn should help to keep the CO2 in solution, no? so proteins shouldnt make too much of a difference.

And now I am even more confused on your question... I think you should try an experiment in which you keg your beer at 34dF and put the keg under 12 psi for 1 week. Then pull back the CO2 pressure before you serve (release head pressure first of course) to about 5 psi and then see if you are getting the mouthfeel that you are lacking.

A higher mash temp will also lead to an improved mouthfeel. If you like stouts or porters lactose is a wonderful addition that will improve mouthfeel. And finally, but definitely not lastly, dry hopping will increase perceived mouthfeel.

Sounds like you need to brew a dry hopped cream porter... mmmmmmm, dry-hopped cream porter, mmmmm

 

[wildwest450]

IMO, co2 bubbles in your mouth is not mouth feel, that's process related. You can have a creamy, velvety mouth feel with a low carbonated beer.

 

[ajdelange]

The key to proper carbonation effects is to have lots of proteins of the proper lengths. Without that you will not get good mouthfeel, head or head retention. Lots of homebrews lack this because protein poor extracts were used or, in the case of all grain, the protein rest was mismanaged.

The other side of the coin is strict avoidance of foam negatives like oils, fats, greases and, surprisingly enough, alcohol itself.

 

[ajdelange]

..which decreases entropy and in turn should help to keep the CO2 in solution, no?

While it's not that central to the discussion, no. For a reaction to take place spontaneously the change in Gibbs energy, dG = dH - TdS, must be less than 0 (at constant temperature). Thus the entropy change (dS) must be positive. Entropy is increased.

 

[SakARow]

While it's not that central to the discussion, no. For a reaction to take place spontaneously the change in Gibbs energy, dG = dH - TdS, must be less than 0 (at constant temperature). Thus the entropy change (dS) must be positive. Entropy is increased.

So I wrote a whole 10 line mad argument to your reply, but realized that we have the same argument. I was referring to the idea of entropy as the state of disorder. Meaning that as the proteins coagulate, they decrease the # of particles in solution and therefore become more ordered. When the solution becomes more ordered, by definition [being the state of disorder or randomness] the entropy is decreased.

I approve of the Gibbs free energy equation bomb. Damn minus sign!

 

[postal_penguin]

So I wrote a whole 10 line mad argument to your reply, but realized that we have the same argument. I was referring to the idea of entropy as the state of disorder. Meaning that as the proteins coagulate, they decrease the # of particles in solution and therefore become more ordered. When the solution becomes more ordered, by definition [being the state of disorder or randomness] the entropy is decreased.

I approve of the Gibbs free energy equation bomb. Damn minus sign!

I think you have it backwards. When proteins coagulate, they reduce the number of ordered "cage" like water molecules around the protein, thereby increasing the degrees of freedom the water has and increasing the state of disorder. Its the same principle as to why oil droplets form, around the hydrocarbon chain of an oil, water adopts an ordered, rigid "cage" and loses degrees of freedom. When the oil clumps together, the amount of water involved in this "cage" is reduced(less oil molecules in contact with water), the degrees of freedom increase and so does entropy. Adding oil to water and watching droplets form does not decrease entropy, it increases it.

 

[boss429]

Thanks all for the replies!

I bottle and I'm comapring to bottles of home brew and micro.

aj,

So you are saying that a protein rest is a good idea if I want to get this "proper" carbonation?

I've realized that I need to do some more reading. If you have any links explaining the effects of protein rest/decoction on carbonation please send me a link.

In the case I'm doing about 92%-95% 2-row is this still your suggestion? If so protein rest at what temp and for how long and why?

This is a real problem so we should try to find a solution for this.

 

[ajdelange]

Although there are many that will tell you that with modern, well modified malts a protein rest is unnecessary I don't believe it because I have had beers that have held protein hazes for months when I skipped them. The idea behind a protein rest is essentially the same as for the starch rests: protein molecules as they come in the malt corn are too large to do what we want them to do in making beer and need to be broken down into smaller bits. The ultimate result of starch breakdown is glucose. The ultimate results of protein breakdown are amino acids many of which the yeast need for metabolism. If they are not present the yeast must synthesize them from others and this is, for example, where diacetyl comes from. Intermediate length chains (polypeptides) are responsible for body, mouthfeel and head. Longer length chains are responsible for chill haze. Thus it is important to try to get the chain lengths distributed properly.

A protein rest of 20 minutes or so at between 122 and 128 °F has always worked for me. If you go too much longer then lysis goes too far, you get too much of the really short and not enough of the intermediates and head and head retention suffer. If not long enough, depending on the malt, you get too much long chain resulting in poor head and possible protein haze.

I don't have any links but the prince of foam and bubbles is Charles Bamforth at UCD. He has written dozens of papers and several books which discuss the subject.

 

[boss429]

AJ,

I totally agree that there are many myths on these forums that people take as true.

I appreciate the info and it sounds legitimate and hopefully Ill get my hands on some of Charles' literature.

apart from my original question..

how is this executed properly?

If I only have a cooler as a mash tun how can I go about this without pouring in boiling water to bring up my temp? is decoc my only option?

And

What system do you use a HERMS or RIMS? or direct? What home brew system is optimum for this?

I know it's kind of a loaded question but I just want to make good beer.

 

[ajdelange]

In a cooler the only thing I can think of would be to strike at 128 (going to the upper end of the range so the step to saccharification rest will be small) and then stepping to the saccharification rest with an infusion. The potential problem with this is, of course, that too much water may be needed for the second step. I mashed in a cooler many years ago but it has been so long I don't remember how it is done in detail.

I mash in a stainless steel drum with a steam coil. A solids pump recirculates the mash. Thus I can step with an infusion or by applying steam or by some combination. As to what the optimum system is - that is a loaded question but I would think HERMS or RIMS systems should work very well. Perhaps some other readers who have those or mash in coolers will comment.

 

[boss429]

yea ill research it how to do the step up properly with cooler.

Thanks for the tips!