Yeast Starter Size

[bcmaui]

OK - had my first boil over trying to make 2L of yeast starter in a 2L flask.

1) It looks like at the moment 2-3L will be my typical yeast starter size - what size Ehrlemeyer should I use? Is this where the foam control comes in handy? If so, how much foam control is used in a 2liter starter?

2) In BCS they suggest 1/4 teaspoon of yeast nutrient. Is this for the 2L or per Liter? I purchased the Fermaid K for this. And do you add more Fermaid K when you repitch to the 5 1/2 - 6 Gallons in the fermenter? If so, how do you use for an average (1.040ish) beer? (Guessing 1-2 teaspoon?) I would think you scale the Fermaid K to amount of yeast being pitched.

3) Do you drop the stir bar in the starter and boil it for 15 minutes as well to sanitize, or clean and star san it on the side and only put it in the flask after it cools down when you pitch the yeast?

4) The stir plate they sell at B3 says it is only for 1 Liter of liquid - is this a general lab thing (maybe stirring things that are more viscous) and is OK to use with 2-3liter of wort, or should I be getting a bigger stir plate?

[Test_Engineer]

1) It's tough, but it is possible to do a 2L starter in a 2L flask. Foam control helps. A couple drops is all you need(1 drop for a 1L starter is plenty, maybe 2 on a 2L starter. It's more about surface tension than doing anything chemically to prevent foam, and the surface area of a 2L flask isn't that much bigger than a 1L flask.

2) I use 1/4 teaspoon per liter of starter, AND a half teaspoon in the kettle 10 minutes before flameout(with the irish moss or whirlflock tab)

3) Doesn't really matter which way you do it. Most sir bars are meant for use when boiling. I prefer to leave it in star san while I am making the starter and add it after it cools, because the stir bar is going to create more sites for boil bubbles to form.

4) Usually they are rated by weight capability and the size of the platform. A 1L stirplate is sized for a 1L flask. Search ebay, there are a ton of good deals on stir plates.

[bcmaui]

Thanks

Also - OK just to let the starter wort cool down slowly - it took about 6 hours for 2 liters to cool down on the stovetop when I left it untouched to go from boiling to 80F - or OK to put in a cool water bath (or refrigerator) to assist in the cool down?

[Test_Engineer]

Thanks

Also - OK just to let the starter wort cool down slowly - it took about 6 hours for 2 liters to cool down on the stovetop when I left it untouched to go from boiling to 80F - or OK to put in a cool water bath (or refrigerator) to assist in the cool down?

I usually use a saucepan, and put the flask in it after the boil is done. I cover the top of the flask with foil that was sanitized, put the flask in the pan, and run water into the saucepan in the sink(start a little warm and switch to cold over the period of a minute or so). Once it it somewhat cool, I throw some ice in the water and let it sit a for a few minutes. You don't have to be too careful, because the flask should be pyrex or bomex, wich means it can handle pretty drastic temperature swings. Just make sure the level of the starter is a bit above the top of the saucepan, or the flask will start to float and you could end up starting over. And the obvious thing would be to use oven mitts when handling the hot flask.

[seanhagerty]

Test Engineer said almost the exact process I use. Foam control does stop the boil over, I boil right in my erlenmeyer flask and have no issues with it. I have a stir plate that has heat and spin capabilities. So, I have my start bar spinning as we boil the water, I have heard of folks getting flat spots on their stir bars by leaving them in the erlenmeyer as they boil the wort, so you may want to skip that, and soak it in starsan until you are ready for it.

Sean

[oneal66]

Just another thought is you could boil your starter wort in a pot and transfer to a sanitized erlenmeyer. You may have more of a chance for contamination this way, but you eliminate the possibility of a boilover. Look at the times and temps for sterilization in a convection oven, and sterilize your erlenmeyer, stir bar, and cover foil in the oven. Boil your wort and add to the erlenmeyer to the cooled flask then chill. Be sure to sanitize a funnel to pour the boiling wort into the flask.

I mean it may be a little more complicated, but you won't boil over and get boilover funk on the oustide of your flask.

As for the flask size on the stir plate, if it says for a 1L flask, it could mean the base is too small to hold anything bigger than that. It may throw the flask off balance. If base is large enough you may not get enough juice from the stirplate to stir over 1L. If it's the latter it may not be as important since you are only looking for enough stirring to keep the yeast in suspension and oxygen in solution.

[TimCA]

I take my 2L starter off the flame place foil over the top and set it into an 5G gott cooler. I then add water and Ice to it. But wait there's more... I then add a smalish "power head'' fish tank pump to the ice water. boiling to 80 in like 8 to 10 min.

I have pics of this but I think it is self explanatory.

Tim