Low Carbonation

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Fleecer

Active Member
Joined
Jun 22, 2014
Messages
29
Reaction score
5
Hi,
Despite following the various online calculators, my last 3 brews have resulted in beers that go flat within a couple of minutes of the pour. To muddy the waters a little, the beers I've brewed have been as a result of left-over grains, so as such don't belong to a 'style'. Predominantly dark, and smattered with chocolate, dark crystal, amber grains, I've erred towards the porter/stout styles, and am using Dextrose to bottle. Added late to the FV, I've used pink grapefruit, orange, and pineapple; all acidic flavours. I'm also using a variety of recycled bottles, which I then cap. I'm storing inside for a week, then in the garage for a further week.
Could the fruits be the problem? are the acids neutralizing the priming sugars somehow? or maybe it's the bottles? (there is a decent fizz upon opening though).

Many thanks
 
From what I read I would say you do have carbonation!
Does the beer fizzes in your mouth? Does it give a pop when it opens? If you pour it from a height, does it give rapid bubbles/foam.

It sounds more like you don't have foam/head retention. You say you have "smattered" your beers with dark malts. Dark malts decreases the foaminess of the beer. A likely suspect.

A post from me in a recent thread:

Alright guys, I did my best to compile a more specific list! Most of it is from this paper:
Shokribousjein, Z.; Deckers, S. M.; Gebruers, K.; Lorgouilloux, Y.; Baggerman, G.; Verachtert, H.; Delcour, J. A.; Etienne, P.; Rock, J.-M.; Michiels, C.; Derdelinckx, G. Cerevisia 2011, 35, 85–101.
I've added the paper as a file at the bottom of this post.

I did my best to take the most important points and either explain or remove things that are just too technical. There probably are many other things, but these are the points that the authors thought to be most important. And I added a few other things of more recent times.
If any thing is unclear feel free to ask and I'll try to see if I can explain it better.

Proteins:

Lipid transfer protein (LTP1) is a protein present in grains. The amount of it is dependent on the specific growing conditions.
This component is a positive influence on foam stability. It does this by enhancing the foam itself, but more importantly by binding fatty acids (which are negative influence).

Hordeins are also present in the grain and are a postive influence if they are present (they are insoluble unless treated with proteolyltic enzymes).

Protein Z has interaction with other proteins (such as LTP1) and in doing so enhances the foam stability.

Non-starch polysaccharides:
Arbinoxylan and -glucan or even oligosaccharides improve foam stability by increasing beer bulk viscosity, thus reducing the drainage of the liquid from foam

Hop acids: Iso--acids of added hops cross-link with protein, and improve foam stability. But if they are used in large amounts (hydrogenated iso--acids) predominantly tetra hopped beers (this is the stuff that large companies use to hop their beer, degrades less rapidly) will degrade to produce a foam that is like “whipped egg-white icebergs” and foam stability is lost. As these acids can produce bad taste “vulcanized rubber” in the final beer, only low addition of hydrogenated iso--acid hop is a useful tool in optimizing foam quality. A high proportion of isohumulone to coisohumulone (Our hop!) will result in more stable foams.

Dry Hopping: Interestingly, dry hopping seems to decrease foam stability. The reasons are not yet well researched: https://hopsteiner.com/wp-content/uploads/2016/06/2016-06_TS_Foamstability.pdf.

Cations:
Metal cations promote beer foam stability and gushing. Multivalent cations (i.e. cations with a charge more than one + or -) improve foam stability via reversible cross-linking with hop acids and proteins. I.e. you have hop acids and proteins floating around randomly, but the cations sort off pull them together making a network of these compounds (giving foam!)

Lipids: : Sources of lipids in beer are mostly malt but also hops and yeasts. By addition of lipids to beer, at first the foam destabilizes but after a rest for 24 h, its foam can be either fully or partially recovered. The reason for this reaction is the presence of lipid binding proteins in beer and the degree of recovery is related to the level of these proteins in beer, their state and the amount of lipid. There is no evidence that essential oils from hops have any impact on foam stability at the levels found even in the “hoppiest” products.

Ethanol (alcohol): The higher the percentage of alcohol the more likely it is for ethanol to disrupt the proteins forming the foam and thus has a negative influence on foam stability in higher alcohol beer.

pH (acidity): The pH of beer has an important impact on foam stability. The proteins and hop acids change their properties according the pH. There is a sweet spot for the pH at which there properties are postive which lies between pH= 3.8–4.6.

Amino acids: The building blocks of all proteins! Basic amino acids (arginine > lysine > histidine) interfere with the protein–iso--acid interaction to inhibit lacing of these proteins. Thus it decreases foam stability. Amino acids in the beer are often the result of autolysis of the yeast. This is caused by leaving the beer too long in the fermentation vessel. It is yet unclear wether or not autolysis rapidly occurs in such small quantities as we brew.
.
Malt manipulation: Higher colored malt contains less foam active proteins available for extraction into beer. This is because higher coloured malts require more intensive heating which causes the proteins to denature (unfold/break down). Thus this is a negative effect.
Roasted malts however seem to be very foam positive (Combe AL, Ang JK, Bamforth CW. 2013).

Removing of acrospires: Acrospires include basic amino acids and trans-2-nonenal (cardboard flavour when a beer ages), so removing them will result in higher foam stability.

Usage of wheat: Addition of wheat to barley causes more foam stability because of: (a) higher protein content of wheat than of barley. (b) the amount of arabinoxylan of wheat is also higher than in barley. Thus the viscosity of finished beer will be higher which causes more foam stability. (c) the size of bubbles will be decreased which results in higher foam stability. (d) the puroindoline (lipid binding protein) level in wheat is high, and in beer there will be less lipids and foam stability will be higher.

Brewing process
Generally: to produce stable foams in beer it is important to extract proteins as much as possible from malt to beer.
Mashing temperature:
If the mashing temperatures are low (<55 ◦C), the proteolysis remains active and causes loss of foam promoting proteins. More basic amino acids remain present in beer which cause foam destabilization as previously mentioned.
If mashing is performed at high temperature (71 ◦C), protease activity is inhibited. Proteins are less degraded and keep their effect on foam stability. All sorts of other pro-foam processes occur. As a whole, mashing temperatures of 65 ◦C or higher have some benefits on foam stability but over 65 ◦C it results in reduced fermentation (lower yield) because of inactivation of some starch hydrolyzing enzymes.

Milling: Wet milling may improve foam stability, leading to increased levels of polypeptides in wort and beer.

Wort boiling (the best is at 103 ◦C): Wort boiling leads to foam promoting of beer by different reactions, such as increased hop acid extraction and isomeration, stopping of malt enzymatic reactions, concentration of wort, and increased Maillard reaction. The Maillard reaction improves foaming stability. The reason is increased glycosylation (coupling of sugars) of protein Z and LTP1 which tends to more flexibility of molecules to move to the air/water interface.

Pitching yeast into high gravity wort: this leads to severe stress on the yeast and reduces secretion of foam promoting proteases, thus reducing foam stability. Again, higher alcohol beers just hate foam.

Yeasts: yeasts excrete proteinase A, which slowly degrades hydrophobic foam promoting proteins (LTP1), leading to foam destabilization.

Pasteurization: causes denaturation of enzymes like proteinase A which is detrimental for foam stability (Evans and Bamforth, 2009) and thus it may favor foam stabilization in beer.

Glassware: Glasses should be clean. Fat residues inside the glass decrease the foam stability. In addition using nucleated (an edging in the bottom) glass favors foam stability and is widely used these days.
 
Last edited:
you have "smattered" your beers with dark malts. This decreases the foaminess of the beer. Most likely the cause.

Gahh - do you have the article for that as this one says this opposite:
http://youngscientistssymposium.org/YSS2016/pdf/Kultgen.pdf

Chocolate malt isn't included there but I've read it does the same because melanoidin helps with head retention. The above does say crystal is foam-negative.

Fleecer - how many volumes of co2 are you going for? I've had beers that haven't carbonated well enough at 10 days in a 20c brew freezer alongside brewing beers but a week later were completely carbonated.
 
I'm storing inside for a week, then in the garage for a further week.
Is that it after you have bottled?
A week to carb (hopefully in a warm place)and a week to condition doesn't sound long enough to me.
Why not give them another week in the warm, then a month to further condition then try again?
I read on here some time ago that longer conditioning helps with head retention because the bubbles are smaller, and I'd say I would tend to agree with that observation.
And are you serving glasses clean i.e. not greasy? If not, that won't help.
 
Gahh - do you have the article for that as this one says this opposite:
http://youngscientistssymposium.org/YSS2016/pdf/Kultgen.pdf

Chocolate malt isn't included there but I've read it does the same because melanoidin helps with head retention. The above does say crystal is foam-negative.

Interesting, thank you! I have not looked at the Combe paper they refer to. That paper is more recent than the review I summerised from.
That being said, I have of course not read all the papers that make up the list of foam effects that I presented. Only the review.
That would be a bit too intense for me, still have lots of stuff to read haha.

But that being said, yeah it appears there is a bit more of a distinction when it comes to coloured malts. Darker malts indeed reduce foam. But roasted malts seem to very much increase it.
I corrected my posts for future reference :), thanks!

But that being said, he also says to have lots of crystal and amber malts. These are usually more dominant than roasted malt. Roasted malts don't really ferment.
 
Last edited:
Thanks guys, you've provided some great insights and ideas. Here are a few answers to the questions raised:
* apologies, I do have carbonation; the issue appears to be head retention
* any amount of CO2 would be nice
* I've dry hopped after 3 days, 100g in 24 litres
* my last batch of 36 litres was split 24/12, the 24 were subjected to an introduction of 6 pink grapefruit. The 12 had no fruit addition and retained a head of sorts for longer
* I didn't use wheat any of the last three brews
* Glassware rinsed after each drink of varying types, not thoroughly washed
* a recent batch was bottle conditioned inside for weeks and has been in the shed for months; same result
 
* Glassware rinsed after each drink of varying types, not thoroughly washed

Aside from what I already said:
This is an easy one to try out atleast. Try to really clean your glass. Soap it up good, get any lipid residues out of it!
Clean it with a clean cloth only used for glasses.
 
my last batch of 36 litres was split 24/12, the 24 were subjected to an introduction of 6 pink grapefruit. The 12 had no fruit addition and retained a head of sorts for longer
Citrus fruits have oil in their skins, called limonene. Oils are known to kill the head on beer. Unless you peel the citrus fruit before you add it to the beer it is not impossible that this might be a contributory reason to your head retention problems.
 
Thanks all, you've given me lots of food for thought.
I'm currently brewing a 24 litre batch containing 5.36kg Maris otter, 400g Dingemanns and 360g Dark Crystal, so will head towards a mid-range CO2 target. Next time I'll probably use wheat and avoid fruit peel.
 
I can't agree with Wouter's observation that dark malts affect head retention. When Guinness had yeast in the bottles you couldn't control the head. It took ages to pour.
BTW I'm not that old. Just remembering my dad pouring Guinness when I was a nipper!
 
I always get a good head with roast malts... Amber, brown, chocolate and black. According to Warminster Maltings the malts that promote head & head retention are... Wheat Malt, Torrefied Barley, Malted Oats, Torrefied Wheat, Cara Malt and Crystal Malts. When using roast malts I like to include some wheat and crystal malt, also I carbonate to 2.4v. Never fails...
 
I can't agree with Wouter's observation that dark malts affect head retention. When Guinness had yeast in the bottles you couldn't control the head. It took ages to pour.
BTW I'm not that old. Just remembering my dad pouring Guinness when I was a nipper!
Well sadly I am that old, :blush: and used to harvest bottled Guinness yeast to brew with, along with White Shield.
 
Cara Malt and Crystal Malts
Crystal is foam negative in the study I put a link to, and carapils is bloody useless according to it. Brulosophy did tests on cara malts and found them to not do what people think.

I can't believe people give such a damn about it.
 
I know for the next few batches I'm going to go with the calculator for the style and increase it by 10%-20%. So if it tells me 100g I'm going to go with 115ish roughly. I'm not sure if It's just that I like it fizzier than what brewers friend is recommending, but i am getting pretty flat beer and I do like a bit of fizz.
 
Back
Top