Author Topic: starter with airlock  (Read 433 times)

Offline macbrewdaddy

  • 1st Kit
  • *
  • Posts: 13
    • View Profile
starter with airlock
« on: May 22, 2014, 12:51:23 PM »
ok, so I guess I had taken it for granted that I woudl put an airlock on top of a starter for liquid yeast.  However after reading up a bit, it seems that that is not the standard practice.  I live in the caribbean where its hot and close to the water, no air conditioner, so the balcony door opposite the kitchen stays open much of the time.  Therefore, it scares me doing just a piece of foil over it for bacteria, dust, and/or bugs getting in.  What about removing the airlock periodically to swirl it and let oxygen in?  Or does using the airlock make the whole effort of a starter pointless?

by the way, I would do the starter in most likely a liter sized empty liquor bottle, I have a stopper that can fit the top.

Offline Steve in TX

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2944
    • View Profile
starter with airlock
« Reply #1 on: May 22, 2014, 12:59:07 PM »
I would forego the airlock. Loosely sealed foil is all you need. Dust can't fall up. Bugs (the kind that crawl and fly) are different. Bugs carry all sorts of bacteria, so you will want to keep them out.
« Last Edit: May 22, 2014, 01:23:32 PM by Steve in TX »

Offline morticaixavier

  • I must live here
  • **********
  • Posts: 7365
  • Underhill VT
    • View Profile
    • The Best Artist in the WORLD!!!!!
Re: starter with airlock
« Reply #2 on: May 22, 2014, 01:19:07 PM »
air born contamination is less of a concern than a lot of people believe. if your equipment that touches the wort/beer is clean and sanitary that's far more important.

starters want as much access to o2 as possible so an air lock is a bad idea.
"Creativity is the residue of wasted time"
-A Einstein

Offline bbesser

  • Cellarman
  • **
  • Posts: 27
  • Engineer to brewer, then back to engineer..for now
    • View Profile
Re: starter with airlock
« Reply #3 on: May 22, 2014, 02:07:49 PM »
I feel kind of silly for asking this question (but my yeast knowledge is the weakest part of my brewing knowledge), but can someone explain why you would apply the foil method for a starter, but not a fermenter?  The basic principal is the same with both conditions so why does it apply to one, but not the other.

Is the idea that the foil needs to allow O2 into the starter because the (liquid) volume of the starter is too small to get enough dissolved O2 to allow for the growth phase of the yeast?
"He who breaks a thing to find out what it is, has lost the path of wisdom." - Gandalf

Offline Steve in TX

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2944
    • View Profile
Re: starter with airlock
« Reply #4 on: May 22, 2014, 02:21:11 PM »
I feel kind of silly for asking this question (but my yeast knowledge is the weakest part of my brewing knowledge), but can someone explain why you would apply the foil method for a starter, but not a fermenter?  The basic principal is the same with both conditions so why does it apply to one, but not the other.

Is the idea that the foil needs to allow O2 into the starter because the (liquid) volume of the starter is too small to get enough dissolved O2 to allow for the growth phase of the yeast?

You want to leave loose foil on a starter so you can get as much O2 as possible. An airlock is needed on a fermenter because you want minimal O2. I have fermented in buckets with the lid resting on top and a half filled growler weighing it down.

Offline morticaixavier

  • I must live here
  • **********
  • Posts: 7365
  • Underhill VT
    • View Profile
    • The Best Artist in the WORLD!!!!!
Re: starter with airlock
« Reply #5 on: May 22, 2014, 02:30:33 PM »
I feel kind of silly for asking this question (but my yeast knowledge is the weakest part of my brewing knowledge), but can someone explain why you would apply the foil method for a starter, but not a fermenter?  The basic principal is the same with both conditions so why does it apply to one, but not the other.

Is the idea that the foil needs to allow O2 into the starter because the (liquid) volume of the starter is too small to get enough dissolved O2 to allow for the growth phase of the yeast?

the difference is that with a starter you are making yeast and making yeast requires as much o2 as you can reasonably manage for the entire time. Yeast metabolic processes are partially controlled by the level of dissolved o2, if there isn't enough they won't reproduce as much and the cells that are created will not be as strong.

when making beer you add o2 at the beginning so the yeast can go through one final reproductive phase before the o2 is used up and they switch metabolic processes to ethanol fermentation
"Creativity is the residue of wasted time"
-A Einstein

Offline Joe Sr.

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2911
  • Chicago - NORTH SIDE
    • View Profile
Re: starter with airlock
« Reply #6 on: May 22, 2014, 02:34:12 PM »
You don't really need an air lock on a fermenter when fermentation is active.  You're producing enough CO2 to keep the air out.

I've pulled the airlock before and used loose foil to keep stuff from falling in. 

Once fermentation settles, I put the airlock back.

For a starter, if you're really worried about bugs you can get one of those foam stoppers.
It's all in the reflexes. - Jack Burton

Offline erockrph

  • Official Poobah of No Life.
  • *
  • Posts: 3975
  • Chepachet, RI
    • View Profile
    • The Hop WHisperer
Re: starter with airlock
« Reply #7 on: May 22, 2014, 03:30:30 PM »
+1 to what everyone else is saying. Bacteria can't crawl up under a piece of foil to contaminate your starter. Plus it allows more O2 in and more CO2 out. Kai did an experiment on this not too long ago:

http://braukaiser.com/blog/blog/2013/03/19/access-to-air-and-its-effect-on-yeast-growth-in-starters/

I will often just loosely cover my bucket fermenters with an undrilled lid during the early stages of fermentation. You only really need an airlock to keep O2 out during aging beyond the active fermentation phase.
Eric B.

Finally got around to starting a homebrewing blog: The Hop Whisperer

Offline macbrewdaddy

  • 1st Kit
  • *
  • Posts: 13
    • View Profile
Re: starter with airlock
« Reply #8 on: May 23, 2014, 07:29:46 AM »
ok, given the style of beer I may go with dry yeast this time, but when I do eventually use the liquid, I'll go the foil method, not sure if I can get a foam stopper here.  Would a new and sanitized sponge cut to fit in the top of the bottle function in place?  I feel like it could be a haven for bacteria, but is at least similar to foam so not sure.

Offline denny

  • Administrator
  • Retired with too much time on my hands
  • *****
  • Posts: 13590
  • Noti OR [1991.4, 287.6deg] AR
    • View Profile
    • Dennybrew
Re: starter with airlock
« Reply #9 on: May 23, 2014, 07:43:30 AM »
ok, given the style of beer I may go with dry yeast this time, but when I do eventually use the liquid, I'll go the foil method, not sure if I can get a foam stopper here.  Would a new and sanitized sponge cut to fit in the top of the bottle function in place?  I feel like it could be a haven for bacteria, but is at least similar to foam so not sure.

The sponge would probably work, but why bother when foil will work for sure?
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

Offline gmac

  • Brewmaster General
  • *******
  • Posts: 2137
  • London, Ontario
    • View Profile
Re: starter with airlock
« Reply #10 on: May 23, 2014, 07:49:22 AM »
I feel kind of silly for asking this question (but my yeast knowledge is the weakest part of my brewing knowledge), but can someone explain why you would apply the foil method for a starter, but not a fermenter?  The basic principal is the same with both conditions so why does it apply to one, but not the other.

Is the idea that the foil needs to allow O2 into the starter because the (liquid) volume of the starter is too small to get enough dissolved O2 to allow for the growth phase of the yeast?

I only foil all my carboys with no issues at all.

Offline jeffy

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2802
  • Tampa, Fl
    • View Profile
Re: starter with airlock
« Reply #11 on: May 23, 2014, 10:34:09 AM »
I feel kind of silly for asking this question (but my yeast knowledge is the weakest part of my brewing knowledge), but can someone explain why you would apply the foil method for a starter, but not a fermenter?  The basic principal is the same with both conditions so why does it apply to one, but not the other.

Is the idea that the foil needs to allow O2 into the starter because the (liquid) volume of the starter is too small to get enough dissolved O2 to allow for the growth phase of the yeast?

I only foil all my carboys with no issues at all.

Same here.  Aluminum foil to cover the carboy opening until primary fermentation is done.
Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)
Homebrewing since 1990
AHA member since 1991, now a lifetime member
BJCP judge since 1995