Another F#%king Yeast Question

[1974Alby]

I will try and keep this simple (just deleted an long and rambling version)...

I make about 2.5L of starter wort by boiling 250g dry malt extract in 2.5 Litres of water for 15 minutes...I then rapidly chill this to room temp and pour into three cleaned and sanitised (iodophor) brown coopers pet bottles. I then use the contents of these bottles to build up a starter, roughly doubling my starter volume every day. I brew 20-23 L batches and aim for a starter volume of about 1L.....(ie DAY 1~200ML, DAY 2~500ML, DAY 3~ 1000ML)However :

1. sometimes when I open one of the bottles of wort I hear a pffft and there is a release of pressure...does this mean it has been infected by yeast and I should not use it to build my starter?

2. how long can I keep this wort in the bottles for and still be able to use it to add to (step- up) my starters? i.e. can I make 5L at a time and use it over months for several starters? or do I need to prepare fresh 1.030 - 1.040 wort every day?

3. If I want to split a liquid yeast into a starter and a few urine sample jars (70ml each) am I better off building a 1.5L starter and storing 3x70ml samples of this, and pitching the remainder? or pouring off 3X 20 ml samples from the smack pack, topping these up with cooled boiled water and proceeding to build a 1L starter from the remainder of the smack pack?

Thats all for now, its late, Thankyou for reading this far!

Al

 

[black_labb]

Firstly I wouldn't be keeping the sanitised wort like that. I would be boiling and cooling the wort when you need to use it. Eventually anything will get some sort of bacteria in it. Remember there was once a nice sterile world outhere until something started to live leading to infestations of creatures from the humble bacteria up to those disgusting humans. Then again you might create your own little world of wort aliens if you leave it long enough.

edit: to answer question 1. it is likely some sort of infection (wild yeast or bacteria). It is also possible that it is air rushing in if you fill the bottle with near boiling water and let it cool after capping causing the liquid to contract (or whatever the term is for a liquid). I wouldn't trust it.

 

[1974Alby]

cheers...I cool the wort in the saucepan (in the sink) before decanting it to the pet bottles via a sanitised funnel. so its not air rushing in..its pressure escaping!

 

[black_labb]

that's not going to be safe to use. beer is able to be kept as yeast turns wort into beer which is a hostile environment for bacteria, but wort itself is a great place for different microorganisms to grow in.

 

[ekul]

when i make starters i get a coupleglass stubbies and some al foil. When the wort is boiling hot i pour it into the cleaned and sanitised stubbies nearly to the top. Then i put a piece of sanitised al foil over the top. And then finally a sanitised piece of gladwrap all held together with a rubber band. Its sort of like a mini nochill

I found a starter that i had prepared in this manner a few months after making it, and amazingly it was still good. I have also found ones that have gone manky after a few months. Anyway, if you do it like this you will be able to use the cooled wort over the next few days. I;ve done this many times and never had an issue.

If you want to use plastic bottles you can by submerging the bottle in cold water as you fill it with hot wort. This will prevent the wort from warping the plastic. But definitely don't cool the wort first and then pour it in, this is just asking for infection.

 

[Thirsty Boy]

Freeze

If you are putting freshly sanitised wort into freshly sanitised PET bottles and sealing them - whack em in the freezer till you want to use them. This will stop any bugs growing in there. There will always be a couple of bugs (frozen or not), thats OK, just dont let them get a head start on the yeast by having the unpitched wort at "growing" temperatures.

Fill PET bottles, freeze the ones you dont want to use immediately and defrost them as required. They will have become neither more nor less sanitary during their period in the freezer.

 

[MaltyHops]

...
3. If I want to split a liquid yeast into a starter and a few urine sample jars (70ml each)
am I better off building a 1.5L starter and storing 3x70ml samples of this, and pitching
the remainder? or pouring off 3X 20 ml samples from the smack pack, topping these up
with cooled boiled water and proceeding to build a 1L starter from the remainder of the
smack pack?

I think the first method you outlined is a bit risky - if something goes wrong with the
starter then you're F#%k-ed

You could also combine both methods - from the new smack pack, put away some
20 ml samples from the smack pack and make a 1.5L starter with the remainder.
If the starter turns out well, then you can put away a few more 70ml samples of the
yeast and spread your risk a bit more widely.

 

[MHB]

You could bottle wort, then pasteurise the bottles.
Just stand them in very hot water for an hour or so, just like the old Vacola food preserving process.
Personally I would choose glass bottles and boil them in a pressure cooker.
MHB

 

[proudscum]

if you have or can get a cheap pressure cooker, can your wort and put it away for later use.i do 7 lt at a time in different size jars as when i need to do a starter(did one last night)i give my flask and funnel an autoclave to sterilize and then put my room temp wort and yeast in.

 

[1974Alby]

Freeze

If you are putting freshly sanitised wort into freshly sanitised PET bottles and sealing them - whack em in the freezer till you want to use them. This will stop any bugs growing in there. There will always be a couple of bugs (frozen or not), thats OK, just dont let them get a head start on the yeast by having the unpitched wort at "growing" temperatures.

Fill PET bottles, freeze the ones you dont want to use immediately and defrost them as required. They will have become neither more nor less sanitary during their period in the freezer.

do you have to re-boil them before adding to a starter?

 

[Steve@PMF82]

Not answering for TB, but for me any wort i have frozen, no matter how sanitary i was prior to freezing i like to give a quick reboil.

If you dont have pressure cookers , autoclaves and borosilicate flasks, to reiterate some of the previous comments, boiling and normal glass are the next best thing.

Old jam jars, screw top mason jars, V8 juice bottles, or strong beer bottles all work well - previously cleaned, sanitized and as close to sterile by repeated boiling one can get.

The thing to remember is that glass does not like extreme changes in temp, so before you go pouring boiling hot wort in there you need to get the glass up to temp.
I have a kettle of filtered water that has been boiled repeatedly over several hours i put a small amount in the glass jar or bottle and shake it up - getting the glass temp up, it then accepts my freshly boiled wort no problems.
I then cap and leave to cool NO CHILL style.
After its chilled you could even go to more extreme length and pasteurize again @ 80degrees for 15 min, for longer term storage.
There is always a hiss of air when opened upon cooling.
I have kept a IXL jam jar full of wort just for experimentation like this for months just sitting in the kitchen.
All that happens was it became very clear as stuff dropped out of suspension.
This does not mean that after the time there was no bugs in there at all, just none that i could see, taste or smell.
Individual situations may vary according to wild yeast population in your area, but i have apple, pear, plum trees, guy up the road has small vineyard.

Good luck

 

[sama]

Gotta get yaself an erlenmyer mate..500ml of wort boiled in a 1000ml flask for 15min,put straight in the sink cools in 15/20min..wash out,repeat next evening etc...pretty cheap these days to.

 

[Thirsty Boy]

do you have to re-boil them before adding to a starter?

no - why would you? It's no more and no less sanitary than it would be if you had tipped yeast straight into it after cooling it down. Which obviously you would be happy to do. In an open container of any description, yes, re-boil. Leave it to defrost on the bench and allow it to get warm and stay warm.... re-boil.

Thaw it and allow it to reach your pitching temp then pitch immediately - its in virtually the same condition it was immediately after you cooled down the wort in the first place. Bugs need a chance to grow, if you haven't given them one then they didn't.

 

[matho]

i have been doing a little experiment i put a little jar in the pressure cooker for 30min with the lid on loosely and i have had it on the window sill for about 3 months and there is a vacuum is still there and no sign of infection,the stuff floating is just break material that got stirred up, not a very useful volume but my pressure cooker can do larger ones.



I have about 5 1.25l soft drink bottles in the freezer with starter wort that i defrost a boil in my flask to make starters when i want, I get the wort from the last runnings from my mash tun when i make a big beer

cheers