brew stuck at 1020

[Dutto]

Henry's Law states:

"At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid."

The second that a fermenter is opened to the air the partial pressure of the brew is exactly the same for the oxygen in the air and the CO2 in the brew. The introduction of Henry's Law doesn't take into consideration:

1. If a brew is "stuck" it means that there is zero fermentation taking place and zero CO2 being produced.
2. Under such conditions, little or no CO2 will be coming out of solution (i.e. zero activity in the air-lock is the first symptom of a "stuck" brew).
3. Under these conditions, opening up a fermenter that is sitting at atmospheric pressure, will expose the brew to air pressure and Dalton's Law of Partial Pressure will apply.

Finally, what happens in the case of "open fermentation" where a brew is exposed to the air all the way through the fermentation process? Personally, I don't use this method, but a number home-brewers and breweries use the method to produce palatable beers.

BTW, I loved the comment from @foxy who said in Posts 18 and 36 "Any oxygen which on the slightest chance may have entered the wort will be driven off by resumption of fermentation."

I may be terminally thick, but I thought the whole purpose of dealing with a "stuck" brew was to re-start fermentation!

I rest my case!

 

[foxy]

In the case of open fermentation the brew does not go all the way through from start to finish. The beer is transfered to a closed fermenter when the krousen dies down.

I think the methods I outlined for rousing a stuck ferment which are the normal procedure is gently stir to rouse the yeast, or swirl, along with a rise in temperature are the usual practice.
By all means carry on doing what you are doing, but it is a poor advice to be offering to other members, one reason why I always will advocate a new brewer to do his own research.

When does wort change to beer?
My rule of thumb answer would be when the aerobic yeast multiplication phase is over and the yeast has started to produce alcohol even though the concentration will be small. In other words its very early on in the primary fermentation phase.
Anyone?

According to Colby.

To rouse your yeast, sanitize a long brewing spoon, racking cane or any utensil that can reach to the bottom of your fermenter. Open the fermenter and stir until the sediment on the bottom is at least temporarily back in solution. Try to stir as quietly as possible, as you don’t want to aerate the wort at this point unless the fermentation stuck before moving more than 1/3 of the way through it’s apparent attenuation range. (Palmer says the same thing)

 

[Rodcx500z]

This brew is no more its gone down the drain, so that's my first failure, trying to figure out what happened, it had no signs of infection it tasted like beer although it had a burnt taste in the background, I am looking at hops and yeast, I bought a pack of mouteka from a hbs I don't normally use after I had used them I noticed the date 2014 crop use by 2016 this hbs has now lost my custom, the other is a duff pack of hog norst, onwards and upwards we go

 

[Dutto]

This brew is no more its gone down the drain, .........

I feel your pain!

I lost two consecutive brews back in the late 1960's (they tasted like vinegar) and it's not something you forget!

 

[kelper]

If air or oxygen diffuses so readily into water, why do aquariums always have an air pump and diffuser? Henry's law refers to equilibrium. Equilibrium takes a long time to reach. Co2 certainly does form a blanket. Stick your nose into a PB when the beer is finished and take a sniff, you'll probably choke. Similarly, petrol vapour is known to collect in boat bilges. Petrol has caused many explosions on enclosed boats. CO2 is used in fixed fire-fighting installations on many merchant ships. After it has been used and all the ventilation fans have been switched back on, CO2 remains in the bilges.

 

[foxy]

If air or oxygen diffuses so readily into water, why do aquariums always have an air pump and diffuser? Henry's law refers to equilibrium. Equilibrium takes a long time to reach. Co2 certainly does form a blanket. Stick your nose into a PB when the beer is finished and take a sniff, you'll probably choke.

I would say that aquariums need air pumps is because the fish and plants are taking up the oxygen, same with my hydroponics the plants need oxygen which is taken in by the roots. In hydroponics the roots of a plant will send out lots of fine roots which float to the top of the water to get the much needed oxygen. As for the equilibrium of co2 and air it is pressure and temperature dependent.
In a bottle for instance the head space is taken up by air, it is a misconception that the yeast will scrub any oxygen from the air in the head space. IT WON'T. Temperature plays a major roll in the air remaining in the head space, the cooler it is the more unlikely the oxygen is to enter the finished beer, this doesn't include handling or shaking.
When making a bigger beer I take more precautions to prevent it from oxidising, the wort at dough in, and under letting and no rapid stirring, transfers under pressure and a co2 blanket.
It is going to take me longer to drink so I need it to last.
Average beers for the home brewer are gone in a few months so if kept below 20 C in the dark and without movement, there isn't any problem. Providing all precautions are taken during fermentation and transfers,

 

[kelper]

The second that a fermenter is opened to the air the partial pressure of the brew is exactly the same for the oxygen in the air and the CO2 in the brew.

Surely you mean pressure, not partial pressure in this sentence? Partial pressures refer to gases, not liquids.

 

[terrym]

If air or oxygen diffuses so readily into water.

Compared to some gases like CO2 which readily dissolves in water by a reversible reaction to form a weak acid, oxygen does not dissolve very well in water. And as a light digression that's why I can never understand people spending ages beating their wort before pitching or even using oxygen injection through a stone, since once the wort is oxygen saturated, which it will be after a short time, further attempts at oxygenation are pointless

 

[kelper]

Does anyone have access to a dissolved oxygen meter? I'd be very interested to know how long it would take for a sample of beer, at the end of fermentation, took to become saturated with oxygen after unagitated exposure to air. I assume the level would be very low or even zero initially and it would slowly rise to 9ppm near the surface. But lower down, I think it would take about 12 hours.

 

[kelper]

This brew is no more its gone down the drain, so that's my first failure, trying to figure out what happened, it had no signs of infection it tasted like beer although it had a burnt taste in the background, I am looking at hops and yeast, I bought a pack of mouteka from a hbs I don't normally use after I had used them I noticed the date 2014 crop use by 2016 this hbs has now lost my custom, the other is a duff pack of hog norst, onwards and upwards we go

I know the feeling. I've twice tried to rectify a stuck fermentation, repitching more than once. 100% failure rate.

 

[terrym]

Does anyone have access to a dissolved oxygen meter? I'd be very interested to know how long it would take for a sample of beer, at the end of fermentation, took to become saturated with oxygen after unagitated exposure to air. I assume the level would be very low or even zero initially and it would slowly rise to 9ppm near the surface. But lower down, I think it would take about 12 hours.

I sometimes use 2 litre bottles, but mostly only take one litre out. So air gets into the bottle. After one day even two days there is no noticeable difference in the beer. But leave it three days or more and you get to notice it increasingly (which is why I don't intentionally leave it that long). Anyway this suggests to me that oxygen diffusion into the beer and the associated spoiling is a relatively slow process and that's only over 100mm or so, let alone the depth of a full FV.

 

[kelper]

I find wine stays drinkable in an opened bottle that is resealed for at least a week. I would agree with you - it's a slow process.

 

[Dutto]

Surely you mean pressure, not partial pressure in this sentence? Partial pressures refer to gases, not liquids.

Sorry, but Henry's Law was quoted.

In physical chemistry, Henry's law is a gas law that states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid.

 

[kelper]

@Dutto

Please read what you wrote - "partial pressure of the brew is exactly the same for the oxygen in the air and the CO2 in the brew." It makes no sense; The CO2 is dissolved, it's no longer a gas; it does not have a PARTIAL pressure.

 

[foxy]

Does anyone have access to a dissolved oxygen meter? I'd be very interested to know how long it would take for a sample of beer, at the end of fermentation, took to become saturated with oxygen after unagitated exposure to air. I assume the level would be very low or even zero initially and it would slowly rise to 9ppm near the surface. But lower down, I think it would take about 12 hours.

I have a DO meter, I bought it for checking the oxygen in the wort when using an air stone and oxygen canister. Only ever used oxygen twice, it is a waste of money and time. Due to the viscosity of the wort the oxygen was forced out within the hour, I did read a report that oxygen was better added 12 hours after pitching when the yeast was acclimatised and ready to get to work.
I wouldn't know how long it takes for oxygen to enter the beer, I would say the best place to research would be on the low oxygen brewing forum. They have a good library too.
http://www.lowoxygenbrewing.com/

 

[Dutto]

@Dutto

Please read what you wrote - "partial pressure of the brew is exactly the same for the oxygen in the air and the CO2 in the brew." It makes no sense; The CO2 is dissolved, it's no longer a gas; it does not have a PARTIAL pressure.

It isn't me that says it matters - it's all the scientists that we have on this Forum. I give you ...

But we are talking of oxygen, getting through the co2! Then into the wort, it just doesn't work like that.
Read up on Henry's Law.

Personally, I never refer people to Boyle's Law, Charles's Law or Henry's Law for the simple reason that, when brewing, they play little or no part in what I do. Maybe it's because beer was brewed for many hundreds of years before anyone started to even think The Gas Laws.

BTW, I didn't even have to look up Henry's Law and what I pointed out is correct. The second that a brew is exposed to the air then the gases within the brew will attempt to reach equilibrium with the gases above the brew as per Henry's Law.

A brew goes "flat" because the CO2 escapes into the atmosphere.

Enjoy.

 

[kelper]

I foolishly tried to oxygenate my stuck wine by adding some oxi-cleaner (percarbonate) it bubbled for hours and I thought I was on a winner. But next morning all bubbles stopped and the wine had changed from red to brown! Down the drain it went.

 

[Dutto]

I foolishly tried to oxygenate my stuck wine by adding some oxi-cleaner (percarbonate) it bubbled for hours and I thought I was on a winner. But next morning all bubbles stopped and the wine had changed from red to brown! Down the drain it went.

Ouch! I very seldom approve of "down the drain" but that sounds like a perfect reason!

 

[foxy]

It isn't me that says it matters - it's all the scientists that we have on this Forum. I give you ...



Personally, I never refer people to Boyle's Law, Charles's Law or Henry's Law for the simple reason that, when brewing, they play little or no part in what I do. Maybe it's because beer was brewed for many hundreds of years before anyone started to even think The Gas Laws.

BTW, I didn't even have to look up Henry's Law and what I pointed out is correct. The second that a brew is exposed to the air then the gases within the brew will attempt to reach equilibrium with the gases above the brew as per Henry's Law.

A brew goes "flat" because the CO2 escapes into the atmosphere.

Enjoy.

"Whatever" I think that Duttos post should be made a sticky. No need to look on line or any further for a stuck ferment Dutto has the answer.

For a stuck brew, the best advice I've ever heard is "Beat it as if it owed you money!"

This aerates the brew and stirs up the yeast. I then add a teaspoonful of Yeast Nutrient, sprinkle in another sachet of yeast and raise the fermenting temperature to the maximum recommended by the yeast producer.

The last brew I had stuck was a Woodfordes Wherry and the system worked a treat.

 

[Ashman]

If I have a beer (any including commercial) in a glass then once finished leave the empty glass overnight. In the morning smell the empty glass dregs - is this smell oxidation of the alcohol?