Hard Seltzer - When to add additional ingredients / safety

[atole]

Greetings! I am quite new to this forum and to home brewing as a whole. I extend my gratitude to anyone who is willing to share their experiences and offer assistance.

I've recently brewed myself a batch of hard seltzer and i've added flavouring concentrate after fermentation has completed just as I serve the drink. The flavouring concentrate is just orange concentrate from my super market but I may want to add other ingredients too (i'm thinking clear whey protein for one of my gym-obsessed friends).

If the additional ingredients are added when the hard seltzer is served from the keg, my understanding is that this is perfectly safe if consumed quickly. However, i'd like to bottle some hard seltzers with the additional ingredients added and send off to some family and friends.

My concern is that though my brew should be sterile (I have sanitised all equipment throughout and will sanitise bottles), the ingredients I add may not be guaranteed to be sterile. I would like to know if this could introduce contaminants when bottled for potentially long periods of time.

If the ingredients I were adding were safe to boil this wouldn't be a concern, because I could just boil it with the hard seltzer before carbonating and bottling. However, given the nature of adding whey protein, which when boiled to a high temperature can denature, this is not an option - it must be added post brew. I'm concerned this could introduce bacteria.

Hoping that some folks can share past experiences or knowledge. I'd really appreciate being pointed towards any resources that can help a new home-brewer understand the details behind sterilisation, and generally how to produce a drink you are sure will be safe for consumption even when bottled for long periods of time. I'm not even sure how to estimate how long the drink can remain in the bottle before it should be thrown out - shelf life I guess.

Cheers!

 

[YeastFace]

What flavourings are you intending on using?

I use Lorann oils, which contain alcohol, propylene glycol, and water.

I'm certain they're aseptic when packaged, and not sure what contaminant would survive in a half empty bottle of what is a hostile environment.

 

[atole]

What flavourings are you intending on using?

I use Lorann oils, which contain alcohol, propylene glycol, and water.

I'm certain they're aseptic when packaged, and not sure what contaminant would survive in a half empty bottle of what is a hostile environment.

I’m using orange concentrate from my local super market plus clear whey protein powder - it’s the latter that I’m slightly concerned about.

 

[atole]

This evening I have learned:

• Pasteurization is the process of food preservation in which foods are treated with mild heat, usually to less than 100 °C, to eliminate pathogens and extend shelf life.
• Whey is derived from the cheesemaking process. Once the milk passes quality tests, enzymes are added to separate the curd from the liquid whey. The liquid whey is then pasteurized and the protein is concentrated and isolated.

Thus, as whey protein is already pasteurized, I think it is relatively safe to add to a homebrew without too much risk of contamination. Would be great to hear from experienced brewers whether you agree with this!

 

[YeastFace]

What's the reasoning for the whey powder? I've only done one hard seltzer, but don't recall seeing that in any of my reading.