[gmac]

I am doing my first stir plate starter today and I was wondering a couple things.
My normal process is just to put a 2L starter in a gallon jug and shake once in a while until the krausen is clearly done, cold crash and pitch.  This normally takes me 3 or 4 days depending on the yeast.  But, with a stir plate, does the yeast finish quicker?  And how do you know it's done?  I'm assuming that the constant agitation results in no visible krausen because the CO2 generated is de-gassed pretty rapidly and this you don't get that big head of krausen but am I wrong?  I did a 2L starter in a 2L flask so I hope I'm right or I'm gonna have some serious spillage.

BTW, first time using WLP013 London Ale.  Major foamer when I tried to get it into the flask.  The CO2 in solution blasted out resulting in a lump of yeast foam that was darn hard to get out.  First time that I've had this problem although I expect it's happened to others before.

[Stevie]

There shouldn't be a significant amount of foam. You will see the CO2 bubbling out. When the bubbles are gone it is done. I normally make my starters the night before and pitch the entire thing. I will sometimes need to step up the starters and will begin earlier in the week.

I've had vials spew on me a few times. Trick is to treat it like a shaken soda bottle.

[denny]

After some experience, I just have faith that the starter will be done on the stirplate in about 48 hours.  Then I put it in the fridge for a couple days (or until I get around to brewing!), decant, and pitch cold.

[philm63]

After some experience, I just have faith that the starter will be done on the stirplate in about 48 hours.  Then I put it in the fridge for a couple days (or until I get around to brewing!), decant, and pitch cold.

+1  -  I've got a WLP300 on the plate as we type, been there 24 hours now and has 24 hours left - I'll always let it go 48 hours just to be sure all of the good attenuating cells have had a chance to floc. Then crash for a couple of days or until I'm ready to brew, but usually not much longer than a week, if I can help it.

[quattlebaum]

If you are doing a 2L starter in a 2L flask you will have blow off. I use fermcap-S and place a small drop in the flask which prevents blow off/foam. Depending on the yeast I also give it 36 to 48 hrs then place in fridge for a few days then decant and pitch. Some of the higher flocc yeast like WLP007 doesn't take as long to crash.

[klickitat jim]

Not to be contrary but my 2000ml starters never blowoff.  I run them between 18-24hrs then cold crash while I'm brewing

[gmac]

I'm none too happy so far. My lhbs usually has good stuff but in this case, the flask has a slight concave bottom so the stir bar is not centering. Needs a dumb bell bar or better yet a decent quality flask. I did run it with water and got a vortex but there is no way I can get it to work properly in wort. Not thrilled and will be letting them know tomorrow.

[Stevie]

I'm none too happy so far. My lhbs usually has good stuff but in this case, the flask has a slight concave bottom so the stir bar is not centering. Needs a dumb bell bar or better yet a decent quality flask. I did run it with water and got a vortex but there is no way I can get it to work properly in wort. Not thrilled and will be letting them know tomorrow.

Stronger magnets in the stirplate may help. My computer fan stirplate doesn't like my 4 liter flask with a 2" bar, but my 30+ y/o high school chem lab stirplate can handle it just fine.

Does the stirplate throw the bar right away? While a light swirl may not be ideal, it's better than nothing.

I have never had much success with the dumbell type. Heavy and loud.

[Jimmy K]

I wouldn't have put a 2L starter in a 2L flask. You still need liquid/air surface area for oxygen exchange or the stirbar isn't as useful. I doubt you have much surface area. However, you're still better off than 2L in 2L with NO stirbar. Next time put it back in the gallon jug.

[gmac]

I wouldn't have put a 2L starter in a 2L flask. You still need liquid/air surface area for oxygen exchange or the stirbar isn't as useful. I doubt you have much surface area. However, you're still better off than 2L in 2L with NO stirbar. Next time put it back in the gallon jug.

Yeah, live and learn. It was 2 fresh vials for a 15 gal batch of 1.038 bitter that was the real starter for a couple big brews of English IPA (mr malty said it was fine). I think we will go to a 10 gal batch. But I probably could have pitched the fresh vials into each and skipped the stir plate altogether at that OG. Might bump it to 10 gals of 1.045 ESB or something. No style concerns as this is for personal use only.

[philm63]

For those slightly larger starters I got a 3L flask - normally my 2L is all I need but as soon as I start approaching 1.7L starter size, I'll switch over to the 3L - same stir bar and plate - works fine and plenty of room to grow if it is so inclined.

My 3L flask also has a slight bump in the middle of the bottom - still works OK but louder than my 2L.

[klickitat jim]

Hmmm I never have a problem. Here's mine today. 2000ml of 1.030 and 100ml of fresh re-used slurry from an APA I kegged this morning. Started at 0900 and high krausen at 1400. I'll chill crash it in the morning and pitch it in tomorrow's IPA.

[philm63]

Wow klickitat jim; now THAT's a full flask!

I just crashed a 1.5L WLP300 in a 3L flask and I have to say; I kept it on the stir plate 48 hours and the marks in the flask indicate the highest it went above the 1.5L mark was about to the 1.55L mark! The action of the stir plate, if working properly and with proper ventilation (keep that foil loose!), will knock the krausen down before it can get out of hand so it would seem that yes, a 2L starter is possible in a 2L flask.

I've had a few go off like a volcano, but this was attributed to the fact I was intending on pitching the whole enchilada so I took it off the plate after about 12 or 14 hours and let it come to high-krausen, then pitched the contents.

So it would seem; if you are fermenting it out - crashing - then pitching, a starter can be just about the full volume of your flask with little to no risk of a blow-over.

[Jimmy K]

But not overflowing says nothing about the cell quality in your starter.

[philm63]

I seem to remember there being a preferred pitch rate for a starter seeing as your goal was to grow a healthy batch of yeast, not make beer. Something like between 50 and 75 million cells/ml of starter wort, Does this sound about right?