Frozen Brew

[OlsBean]

Like a complete numpty I’ve managed to freeze a Lager that was cold conditioning in a Fridge after the thermostat failed. Researching seems to suggest that this may have killed the yeast, if not all of it, a good proportion of it. I have some more of the same yeast, (Mangrove Jacks M84) and I was wondering if I should use it and if yes, then when should I re-add it, now (I want to continue lagering for a couple more weeks) or later when I bottle?

Any advice would be welcomed.

TIA

 

[IainM]

I've done that on an ale and it turned out fine, and again with a starter which was very viable, as in crawling out the Erlenmeyer within 30 mins of stepping up. I read somewhere that you lose about 10% of viable yeast with every freeze/thaw cycle, which is certainly consistent with my experience and would suggest that you'll be fine.

 

[Dutto]

Luckily, this has never happened to me, but having searched "freezing live yeast" there are dozens of sites that tell you how to do it - for bread yeast! So, working on the "yeast is yeast" principle maybe you are going to get away with it.

Personally, I would:

• Slowly raise the temperature up to the minimum specified for Mango Jacks M84. (i.e. 10*C)
• Put the spare packet of yeast in the fridge to acclimatise it in case you need to use it.
• Leave the brew for a week to see if it starts to ferment.
• If there is no sign of life after a week you don't really have a choice because the yeast has either been made inactive or it has been killed. In this case it's pointless bottling it because there would be no viable yeast to carbonate the brew so sprinkling in the spare yeast and leaving it for another week seems to be the way to go.
• If there are signs of life then take an SG and bottle it if it is at the correct FG. There should be sufficient yeast available to carbonate the bottles (albeit very slowly) so there is no need to add any extra yeast.

Hope this helps.

 

[Bigcol49]

Hi!
I assume that fermentation is complete, as you are cold conditioning the beer.
If you are going to leave the brew to lager for another two weeks, fill a bottle, prime it and leave it to condition.
After two weeks test the bottle for carbonation - if you're unhappy with it, add rehydrated yeast to the main batch before bottling.

 

[OlsBean]

Thanks for the advice, fermentation was indeed complete, it took 3.5 weeks including an Diacetly rest. I'll try and extract 200ml or so (not easy as it's in one of those narrow neck Carboys) and put it in a crushed plastic pop bottle with a little sugar to see if it expands it in the warmth at all. As a side note I have now bypassed the fridges thermostat and I am using an Inkbird to control it, something I should have done in the first place!

 

[mickthetrick]

it will be fine.
i done it last year when using a new fridge as the beer carbed up and was good.

 

[JonBrew]

I think your results will depend to what extent you froze the beer.

I've done this twice. First time was a DIPA; the beer only partially froze, i.e. there was significantly more unfrozen than frozen. No additional yeast added. It carbonated fine and the resultant beer was one of the best I've ever made.

The second time was more recently. Beer was a Dark Mild; the beer froze almost completely solid. No additional yeast added. The beer tastes fine but it hasn't carbonated all that well and the head retention is awful. I've heard a number of folk say is the thing you lose most is the head retention.

If you think you've frozen the majority of the beer, I'd be tempted to add some more yeast at bottling.

 

[BeerCat]

I have bottled before leaving a large chunk of ice in the FV and making stronger beer. Was fine and i have also left it a day in the kitchen to thaw and was fine. Do not worry.

Edit. Just read @JonBrew post and mine was only partially frozen. Lost around 3 or4l from a 23l batch.

 

[Bigcol49]

I have bottled before leaving a large chunk of ice in the FV and making stronger beer.

Hi!
USA farmers make applejack by continually allowing cider to freeze partially and removing the ice.

 

[Nicks90]

Hi!
USA farmers make applejack by continually allowing cider to freeze partially and removing the ice.

Hang on one minute..
So instead of setting up a highly illegal still - I could brew something and bung it in a temp controlled freezer at -2c and every day scoop off the water ice and be left with essentially a distilled spirits?

 

[GerritT]

Yes. But it still might be illegal. And perhaps prohibited on this forum.

Hang on one minute..
So instead of setting up a highly illegal still - I could brew something and bung it in a temp controlled freezer at -2c and every day scoop off the water ice and be left with essentially a distilled spirits?

 

[Bigcol49]

And perhaps prohibited on this forum.

Hi!
I did not endorse this practice nor suggest that any member follow it - it was merely a statement of fact.

I could brew something and bung it in a temp controlled freezer at -2c and every day scoop off the water ice and be left with essentially a distilled spirits?

You mean you've never heard of applejack?
The method is known as freeze distillation - there is a health warning: Freeze distillation concentrates not only the drinkable ethanol but also the methanol and fusel alcohols (byproducts of fermentation which distillation by heat separates out); these latter can be unhealthy. Many countries prohibit freeze-distilled applejack as a health measure. (Wikipedia)

 

[Jakeyboi]

I accidentally partially froze a corny keg. When I drew off the first few pints they were absolutely fantastic, even though they had thawed I think a big % of the water content was still floating up the top, and I had a rich concentration of beer down the bottom. Tempted to try and replicate that again.

 

[Slid]

Yes. But it still might be illegal. And perhaps prohibited on this forum.

I think we have had this a few times on the Forum.

Our specific objection to discussion of freeze concentration is fairly simple.

We have a lot of "new" brewers on this Forum and they are prone to making what might be termed "mistakes" in the brewing process, often with temperatures. Such mistakes can lead to the production of by-products that can be distinctly harmful.

These mistakes are only going to be made worse by concentration of the stuff that has been made, hence the subject is not encouraged for discussion.

Hope this explains.

 

[Dutto]

Hang on one minute..
So instead of setting up a highly illegal still - I could brew something and bung it in a temp controlled freezer at -2c and every day scoop off the water ice and be left with essentially a distilled spirits?

Yes and No. Sorry but separating Ethanol/Water mixtures are not easy.

"Yes." freezing an Ethanol/Water mix will result in some of the alcohol being left behind as a liquid when the water freezes to a solid.

"No." the alcohol left behind will still contain a load of water.

To use this system to produce what may be considered "distilled" ethanol would require you to freeze the mixture about twenty times. At that stage you may have a liquid that is at 40% alcohol; but there will be so little of it that you will wonder why you bothered.

Also, a domestic freezer wouldn't be able to get the temperature down low enough to freeze the mixture much past the 15% alcohol.point. As you can make wine at that strength, the misnamed "Freeze Distillation" isn't currently illegal in the UK.

Also, as already pointed out, the by-products of Methanol and Fusel Oils (both dangerous substances in high concentrations) will stay with the Ethanol and thereby be concentrated up as well.

So, in synopsis, "Yes" it can be done with a lot of effort and "No" you can't make "distilled spirits" in a domestic freezer.

 

[Slid]

Well said, Dutto and well put.

My thanks for this.

 

[Drunkula]

Just have to point out that there's also ethanol being 'concentrated' alongside the methanol at the same ratio as it was in the original drink and so the danger of it is an absolute myth unless the original drink was dangerous.

 

[Dutto]

Just have to point out that there's also ethanol being 'concentrated' alongside the methanol at the same ratio as it was in the original drink and so the danger of it is an absolute myth unless the original drink was dangerous.

Er ... "Yes" and "No" again. Sorry.

The properties of the two compounds means that they boil and freeze at different temperatures and have different ranges as follows:

Methanol
Freezing Point = -97.6*C Boiling Point = 67.4*C Range = 165.0*C

Ethanol
Freezing Point = -114.14*C Boiling Point = 78.24*C Range = 192.38*C

A mixture of these two compounds will therefore freeze and boil at different temperatures.

The difference in the Boiling Point forms the basis of commercial distillation activities. The low temperature end is removed to ensure that no methanol enters the finished product and the mixture is only heated to a given temperature to ensure that a minimum of fusel oils are carried over with the ethanol.

In "Freeze Distillation" the Methanol will tend to solidify and therefore be removed before the Ethanol in the same manner as an ordinary distillation process.

However, as previously explained:

• Ordinary distillation of alcohol is illegal and discouraged by this Forum. and
• Freeze Distillation isn't possible with a domestic freezer. (Check out the freezing point of the two compounds if you need any more proof.)

Finally, why is the production of Methanol and Fusel Oils seen as a problem?

They are both highly toxic substances and both of them are produced during normal fermentation. (They are responsible for the next days hangover.) The situation becomes dangerous under two main circumstances:

1. Almost anything with sugar in it will ferment. In some countries they ferment potatoes to make vodka whereas in others they ferment sugar cane to make rum. Both of these processes produce high levels of methanol and fusel oils and require very careful distillation and filtration to ensure that the finished product doesn't blind or kill the person who drinks it.
2. The fermentation process itself can seriously increase the production of methanol and fusel oils regardless of the substance being fermented. This includes the yeast used and the temperature at which the fermentation process is carried out.

So this is why concentrating up the alcohol contents of a brew is potentially dangerous and distillation has been made illegal in the UK.

PS

Never forget that Ethanol (the alcohol which we are producing in all of our beers, lagers, ciders and wines) is also toxic if you drink too much!

 

[Thumper]

Just have to point out that there's also ethanol being 'concentrated' alongside the methanol at the same ratio as it was in the original drink and so the danger of it is an absolute myth unless the original drink was dangerous.

The dose makes the poison, to use the old cliche. The danger of concentration is that you get a bigger dose in one mouthful. The ratio off methanol to ethanol is irrelevant, what matters is the total amount of each you have in your system. Methanol is poisonous in lower doses than ethanol.

 

[GerritT]

The dose makes the poison, to use the old cliche. The danger of concentration is that you get a bigger dose in one mouthful. The ratio off methanol to ethanol is irrelevant, what matters is the total amount of each you have in your system. Methanol is poisonous in lower doses than ethanol.

And ethanol is an antidote for methanol.