Freezing before fermentation

[GoldenBrewer]

Hello! I am gearing up to crush and press a few hundred pounds of apples this weekend with friends at my house. I have a done this twice in the past 10 years but today I am dusting off my cider making neurons.

In the past I added sulfites to the fresh pressed cider, waited 24 hours, then pitched yeast.

At the LHBS yesterday and the man behind the counter told me he has simply frozen the fresh juice in order to kill off the microbes, then thawed and pitched yeast... no chemicals or pasteurization necessary. I have never heard this before, nor would I expect freezing to kill off all the microbes, but he swore by it. I searched the web for this method and came up empty handed (everything came up applejack methods). Anybody have experience, thoughts, suggestions? THanks!!

 

[ProblemChild]

Leave head-space in the containers you freeze in. The sugar will separate and the expansion caused by freezing (if you don't allow for it) will blow the lid off the top and the stuff that comes out first is the sugar - that or the sides will split. Ran into that when freezing fresh-pressed cider in plastic gallon jugs. The containers of course contributed to the problem, but freezing was involved....

 

[GoldenBrewer]

I would freeze in 6.5 gallon plastic fermentation buckets with 8 inches or so of headspace. Do you think it would split the fermentors?

 

[ProblemChild]

Honestly I cannot tell you.

Water has about a 9% expansion rate, so this seems reasonable as you have allowed for that much expansion.

I would be inclined to put a hole in the lid or similar to let air escape as it is compressed by the expanding ice.

 

[GoldenBrewer]

I really appreciate the suggestions for taking into account freezing expansion. I would still like to know if anyone has used freezing as a method for killing microbes or if the LHBS fellow is guiding me into the unknown.

 

[ten80]

No, your LHBS fellow is incorrect. At best, freezing at standard household deep freezer temperatures (e.g., -20F) will kill a only small portion of the wild yeast and bacteria. The juice will begin to ferment naturally when it thaws. This is no different than pulling a frozen steak out of the fridge and forgetting it on the counter for 3 days... it will definitely start going bad as microbes inside the package re-awaken.

Your options for home sterilizing the juice prior to fermentation without the use of sulfites include filtration and heat pasteurization.

Another option for a "clean" fermentation is to lower the pH to about 3.4 (if not already there) and pitch a large amount of wine yeast. The wine yeast will dominate over wild yeasts in a low pH environment and will produce alcohol to stave off wild bacteria. Your juice will still probably go through malolactic fermentation and has a higher risk of turning to vinegar (acetic acid) if exposed to oxygen. The risk for the latter is low as long as you keep your airlock full.

 

[GoldenBrewer]

Thank you ten80, that is more in line with what I originally thought. Freezing can't be a way of sterilizing anything, just a means of slowing down the microbes. I am going to crush some camden tablets in the must and wait 24 hours before pitching my yeast. And thanks for the heads up to ensure the airlock doesn't dry up and expose o2.

 

[AzOr]

No, your LHBS fellow is incorrect. At best, freezing at standard household deep freezer temperatures (e.g., -20F) will kill a only small portion of the wild yeast and bacteria. The juice will begin to ferment naturally when it thaws. This is no different than pulling a frozen steak out of the fridge and forgetting it on the counter for 3 days... it will definitely start going bad as microbes inside the package re-awaken.

Your options for home sterilizing the juice prior to fermentation without the use of sulfites include filtration and heat pasteurization.

Another option for a "clean" fermentation is to lower the pH to about 3.4 (if not already there) and pitch a large amount of wine yeast. The wine yeast will dominate over wild yeasts in a low pH environment and will produce alcohol to stave off wild bacteria. Your juice will still probably go through malolactic fermentation and has a higher risk of turning to vinegar (acetic acid) if exposed to oxygen. The risk for the latter is low as long as you keep your airlock full.

Yup. Freezing will slow, if not halt bacteria and wild yeast but not pasteurize.
Remember, some people freeze their wine yeast for storage.
I’ve used frozen non pasteurized juice many times. I thaw then pitch yeast. It’s a bit of a safeguard.

 

[GeneDaniels1963]

I really appreciate the suggestions for taking into account freezing expansion. I would still like to know if anyone has used freezing as a method for killing microbes or if the LHBS fellow is guiding me into the unknown.

I think freezing is "hit or miss" for killing microbes. It seems to work well on berries, but it did not work on some pears I did this year. The microbes still infected the cider. So, freeze for ease of working the apples, but use sulfieds too.

 

[MarkKF]

I’ve frozen cider in gal. jugs. But wanna freeze 6 gal. Will a bucket hold or crack?

 

[ten80]

5 gallons of cider in a 6-gallon bucket works nicely without cracking or overflowing. I've also frozen cider in plastic carboys (NO GLASS!!!!) and 5-gal corny kegs (fill about 4.25 gallons).

 

[fishybeer]

Quite a helpful thread. I had the same question. I've pasteurized before and will continue to do so. Home pressed juice from my own trees, so lots of opportunity for uninvited guests to climb aboard...