I bought some 30l Speidel fermenters because I’m making cider and want to mature it over six months. Moving from cheap fermenting buckets with bubble airlocks, I’m panicking because I cant see or hear any movement coming from the big Speidel airlock. I’ve re-fitted the lid, checked the seals, pushed the bung in as far as it will go, so I believe everything is airtight. SG is dropping and there is krausen on top of the liquid, so it’s fermenting.

Do big Speidel airlocks ferment quietly?

Don’t know but I wouldn’t sweat it. There will be enough CO2 being produced to maintain a “safe” environment inside the fermenter. Opening the lid and faffing around with it all would present more of an opportunity for nasties to get hold.

From what you say, all sounds good. Investigate the airlock issue when this batch is safely bottled/whatever.

SG is dropping

This is all you need to worry about 🙂

as allthepies says

Opening the lid and faffing around with it all would present more of an opportunity for nasties to get hold.

What I’m most concerned about is long-term storage of the liquid in these fermenters. During primary ferment, oxygen getting in isn’t a big deal, in fact it can help weak yeast cultures get going. But I keep the cider on its lees for over six months in the same fermenter and I bought these fancy ones so that it reduces the chance of oxygen permeating through the plastic or any air gap. Hopefully the airlock isn’t visibly or audibly active because the wild yeasts off these early season apples are pretty chilled out.

Think I’ve sussed it. I filled a spare airlock with water and blew through the inlet hole and the orange cap just lifted. I had to force air fast to get it to bubble. So as long as the orange cap stays up, the fermenter’s airtight.

As you’ve said, you’ll have outgassing during primary so no issue.

The old adage of co2 forming “protective blanket” against co2 is (I believe) incorrect and so oxygen getting in becomes an issue after primary.

Speidels are more permeable than both glass and stainless steel fermenters, so you’ll have oxygen getting in through the walls of the fermenter.

You’ll also have oxygen getting in through your airlock, whatever you fill it with and any plastic/rubber stoppers or seals you have in place.

i.e. regardless of what you do, you won’t have a “sealed” fermenter.

It’s simply a matter of how long and your first batch should give you a good indication 🙂

Cheers, good points. I guess the orange cap is lifting due to air pressure and all I can hope for is the Speidels do a better job of keeping air out than cheap 5 gallon buckets. I stored last year’s in three cheap buckets and only one spoiled with some film yeast forming, but when all blended up it was still very drinkable, just a little funky, which is how I like it!