Looking for clarification - sterile filtration vs. pasteurization (again!)

[Matt Cavers]

Hi all - I've been combing through past threads that deal with the question of whether potassium sorbate + potassium metabisulfite + sterile filtration can replace in-bottle pasteurization for shelf stability of backsweetened ciders. I'm not looking to reopen the topic, just simply looking for help interpreting one argument that's been made many times on these threads. It goes like this: sterile filtration etc. prior to packaging should not be a substitute for in-package pasteurization because packaging can introduce contaminants which will then kick off refermentation in the package. Makes sense.

This is where I get hung up: I make cider in a brewery (and I make beer too), and like most small breweries in Canada, we don't pasteurize our beer. Our beer is packaged when it's finished fermentation, but there's always a significant amount of residual sugar in it - just like pretty much all beer. Granted, the sugars left behind post-fermentation are complex ones that our ale yeast can't do anything with. But certain contaminants can certainly ferment these residual sugars and cause unplanned fermentation in the bottle or can. We haven't had this problem (thankfully) because we are super serious about sanitizing our packaging equipment, but it's definitely not unheard of. So here's my question - is it actually riskier to package (and not pasteurize) a back-sweetened, sterile-filtered, sorbate etc. treated cider than it is to package an ale with the same SG? If so, why - is it just that the sugar source used in back-sweetening (whether juice or whatever) is a simpler sugar than the residual sugar left behind in fermented beer?

I hope it's clear that I'm not trying to beat a dead horse here - I just haven't seen this particular question answered before. And I'd like to really understand this before I commit to building a pasteurizer! Thanks everyone.

[Claude Jolicoeur]

I don't myself use the sterile filtration + chemical stabilization process - this is more for larger cideries that can afford the equipment.
But I know here in Quebec this is the standard, no one among the bigger guys does pasteurization.
And in particular, for ice cider that contains 130 to 150 g/L of residual sugar, if it wasn't reliable it would be a real mess!
You however need to make sure your lines, filler and bottles are sterile - often steam is used for sterilization of everything after the filter.
Claude

[Andrew Lea]

On 07/12/2017 00:00, Matt Cavers wrote:

> So here's my question -
> is it actually riskier to package (and not pasteurize) a back-sweetened,
> sterile-filtered, sorbate etc. treated cider than it is to package an
> ale with the same SG? If so, why - is it just that the sugar source used
> in back-sweetening (whether juice or whatever) is a simpler sugar than
> the residual sugar left behind in fermented beer?

Yes. As you have pointed out, the residual sugars in beer are
oligosaccharides which are very hard / impossible for most yeasts to
digest. Whereas in cider and wine, all the sugars are simple mono or
disaccharides (glucose, fructose and sucrose) which any self respecting
yeast will blaze through like a dose of salts given the chance.

Here in the UK, larger cider manufacturers all sterile filter and bottle
nowadays. They don't use sorbate because it's ineffective against the
worst spoilage yeasts like Z. bailli. But to make sterile filling work
successfully 100% of the time, the entire final filtration and packaging
line has to be seen as a single sterile unit. This means precautions
like CIP throughout, peracetic acid for surface sterilisation of bottles
blown off with sterile air, positive pressure of sterile filtered air in
the bottling line etc etc. It's like an operating theatre in terms of
cleanliness. It has to be. They've been doing this for the last 30 or 40
years and they know how to make it work.

But this technology isn't cheap and small manufacturers can't afford it.
So pasteurisation is the dependable fallback. It is easy to implement
and it works. You can even do it reliably in your kitchen ;-)

Andrew

--
near Oxford, UK
Wittenham Hill Cider Portal
www.cider.org.uk
www.amazon.co.uk/Craft-Cider-Making-Andrew-Lea/dp/1785000152

[Wes Cherry]

Velcorin is an alternative to pasteurization.

Dosing Machines are quite expensive though ~$74k.

http://www.scottlab.com/product-307.aspx

I know of one large cidery around here that successfully uses velcorin instead of pasteurization.   They probably also sterile filter and steam sterilize their line.

And please don’t use sorbate.  At required doses, It just plain ruins the flavor of cider with its bubblegum flavor notes.  

-'//es Cherry

Dragon's Head Cider

Vashon Island, Wa US

www.dragonsheadcider.com

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[Matt Cavers]

Claude, Andrew, Wes - thanks! This does help me understand the situation better. I note that all of you quite deliberately use the word "sterile" rather than "sanitary," and I'm aware of the distinction. We keep our canning line very nice and clean and we sanitize the whole works with peracetic before and after every use, and rinse our cans with peracetic, and so on, but I wouldn't call the operation sterile as it's open to the air in our warehouse. Thank you, Andrew, for confirming my suspicion that the type of sugar used in backsweetening renders such ciders more vulnerable to refermentation than beer with its residual complex sugars.

The solution is simple - I'll take each and every pallet of can back to my house at the end of the day and pasteurize them on my stovetop as Andrew suggests! No, no, now I'm going to get serious about building a pasteurizing bath. Thanks again to all of you.

[William Grote]

Tom Oliver told us at Cider Days that he pasteurizes many of his ciders and perries, and no one I know of complains about those :-)

If you do build a bath make a PU monitor out of an Arduino and two thermistors, then you can pull the cans when they hit the exact number of PUs you wish - you just need a dummy can filled with water and one of the thermistors -