A few questions about using a stir plate for starters

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austinb

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I just finished a homemade computer fan stir plate in a cigar box and I had a few questions about making starters with it.

1st question: How far in advance should I make the starter, is it still 24 hours before pitching?

2nd question: How big of a starter do I need for 10 gallons? I have a couple jars of washed California ale yeast I plan on using for the starter. I do not yet have a flask so I will be making the starters in growlers. My 4L carlo rossi bottle does not work because even if I start slow the stir bar ends up being thrown to the side because of the concave. My 1/2 gallon growler does work though so I was wondering if 1/2 gallon stirred starter would be good enough for 10 gallons because of the higher yeast count from being stirred?

3rd question: If the 1/2 gallon starter is not enough for 10 gallons could I start one a couple days before and then take it off after 24 hours and put an air lock on it until it is ready to pitch the next day? This way I could make one, then when it is done pull it off and make another so I have a total of 1 gallon of starter for 10 gallons of wort.
 
You should check out Mr Malty. On the Yeast Tools page there is a starter calculator that will tell you how big your starter needs to be based on batch size, OG, and starter type.

1) I like to make my starters the weekend before I brew. I let it spin for 2 days to fully ferment, pour it into a 2 liter bottle, and put it in the fridge. On brew day, I pull it out of the fridge to let it warm a little. Then I decant most of the liquid and pitch. If you are making the starter to pitch immediately, you should pitch at high krausen which should be somewhere near 24 hours. Just throw the thing in your fermenter and let em work.

2) Gravity effects starter size but you should need about 1 liter for a 5 gallon batch and 2 liters for a 10 gallon batch. Make sure there is enough room for a very active fermentation. Your starter will ferment aggressively and can make a mess. I don't make starters bigger than 1L in a 2L flask. If I need more than 1L I'll make 2 starters. This may be overkill but I'd rather make a 2nd starter than clean up a mess and deal with whoever doesn't like that I made a mess.

3) If I need more than 1L I'll make half of the starter and put it in a 2L pop bottle and keep it in the fridge. Then when the 2nd half is finished I decant the liquid from the first starter and add the second one right to the first. There is no reason you couldn't put the 1st half in the fridge and pitch that when the 2nd half is at high krausen.
 
Ok two more questions.

1. You mentioned 2L soda bottles but I don't drink much soda so I don't have any handy, can I just put a sanitized cap on the growler and stick that in the fridge? Or since I do have the correct sized stopper would an airlock be better?

2. I opened up one of my jars of washed California ale yeast today and there was mold around the rim of the jar, it didn't look like it was actually in the jar and just around where the screw top was but I didn't want to risk it so I dumped that one. I then opened up the other jar I had and there was no mold so I pitched that one instead. However, that was my last jar, so my question is when I start the next one tomorrow can I just pour off some of the slurry from today's batch to get the next batch going tomorrow?

Thanks for all your help...I'm really looking forward to getting this whole thing figured out and hoping it helps me to get healthier fermentations.
 
i would put the growler right in the fridge, fewer transfers reduces the chance of contamination, but don't close it tightly as it can still be slowly producing or releasing co2. i usually double up the tin foil and then rubber band it tightly before fridge time
 
So its been about 12 hours and my stirred starter still has not formed any krausen. Is this normal or is my yeast probably bad? The yeast was washed about 6 months ago but I've heard of people using washed yeast up to a year later so I thought it would be ok. Since I was hoping to brew tomorrow should I go pick up a fresh vial from the LHBS? If so should I just pitch it into the starter I already have going or should I make a new starter?
 
Stirred starters often don't form much krausen at all- the foam gets beaten back into the liquid before it has a chance to stick around. You're almost certainly fine. I like to make my starters 48-72hrs in advance so I can toss them in the fridge overnight to cold crash and decant the spent beer off the yeast cake. Before you brew you should be able to stop it stirring and let it sit for a few minutes and see a small yeast cake start to form on the bottom. It won't be as big as if you had cold crashed the yeast out, but it should be noticeable as an indication things worked.
 
1 Any sanitized constainer would be fine. I use two liters because they fit in the fridge nicer than a flask. My starters vary in how much foam rises. Sometimes it looks like nothing. Sometimes there's more than nothing. Once it came out of the top of my flask and made a mess all over the counter.

2 Not really sure what you're trying to say.
 
Ok, I stopped the stir plate for about an hour and there was about a 1/2 inch yeast cake so maybe it is fine.

Since I need to do 2 starters for 10 gallons I was wondering if I could use some of the yeast from the starter I have on the stir plate right now for the next one I will start later today by pouring a little bit of the current starter into the next starter?
 
austinb said:
Ok, I stopped the stir plate for about an hour and there was about a 1/2 inch yeast cake so maybe it is fine. I was wondering if I could pour some of this starter off into the next starter I will make later today?

If you are talking about the liquid or beer then no, the sugars have already been fermented out, hence the nice large yeast came at the bottom.
 
If you are talking about the liquid or beer then no, the sugars have already been fermented out, hence the nice large yeast came at the bottom.

What I meant was I would make a new starter with more DME like I normally would and then pour just a little bit (maybe 1/4 cup or so) of the first starter into the new one. I would pour it when the first starter was still well mixed before the yeast had settled out.
 
Yes, you can pour off the liquid into another vessel and crash that. Leave behind a 1/4" of yeast and add more wort.
 
Well just thought I would post my results. I was a little disappointed by the results of this experiment but I think that was due to a low viability of the yeast I was using and only running each starter for about 18 hours when I probably needed more time with the old yeast.

The first starter had a decent yeast cake when I let it settle but I have a feeling part of it was the yeast I pitched into it and some of it was trub. Before crash cooling the first one I swirled it real good to get the yeast well mixed and poured it to another growler. I left 1/4" of this slurry at the bottom of the growler and added some fresh wort and used this as my second starter (since I was doing 10 gallons I needed 2). I pulled the second one off the stir plate about an hour before pitching and almost nothing settled on the bottom so I was worried it hardly had any yeast. I decided since the first one likely had a little more yeast in it to mix the two together in a larger growler, I then swirled it to mix it really well and pitched half of the whole growler in each carboy.

So this morning, the day after brewing I still have not seen any fermentation activity. In the past I've normally seen a little activity within about 6-8 hours when pitching non-stirred starters from yeast I knew was good. I've also normally seen activity the next morning when pitching a packet of dry yeast directly in each carboy. If I don't see any activity within the next few hours I'll probably make a run down to the LHBS and pick up a couple packets of US-05 to get this one started.

Anyway I think in the future I will try and use fresher yeast and also try and start a week before brewing so I have time for each starter to finish and let them crash cool so I don't have to pitch the whole mixture. If I don't have a week to get it started I will at least try to start with fresher yeast. Right now I am using the stir plate to try and propagate some pacman from the dregs of a 22oz bottle of chateau rogue single malt ale. I will try and build this up and hopefully pitch it into my next brew rather than have it sit in the fridge for 6 months.
 
You are probably correct that there was not enough time to have significant cell division. How long was each one on the stir plate? Was it 18 hours each?
 
I just added up the hours, the first one was on for 19 hours and the second one was on for 22 hours. I guess I was under the impression that doing a starter on the stir plate would require a lot less time than a regular starter. We used to use stir plates at the brewery I worked at to fully ferment a sample of beer down to its final gravity. We would compare that number with a non-stirred sample every couple days until the non-stirred sample was within a couple points of the FG of the stirred sample, this was basically so we knew when each batch of beer was done. When I did that it only took 4 hours to fully ferment each sample but it was usually almost done anyway and we put a crap-ton of yeast in each sample. So thats where I think I got the idea that it would take way less time with a stirred starter.

Anyway, I didn't want the beer to sit for much longer without fermenting so I pitched a couple packets of dry yeast yesterday and there is now about 1/2 inch of krausen in each carboy.

Next time I will try and start with fresher yeast and I will try and start at least 4 days before brewing so by starters have sufficient time to get going.
 
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