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Question about my yeast starter

Last night I decided to try putting my flask directly on the electric burner to make my 1L starter for the 1045 pale ale i’m planning on brewing tomorrow. Prior to reaching a boil the flask started making sounds that caused me to get nervous so I poured the flask into a bot to finish my boil. Finished the starter and poured back into flask. I noticed during my “experiment” that I boiled off about half of my original volume. I’m using recycled yeast from my last batch so I poured the boiled/cooled water from the mason jar back into my starter to make up for all the boil off. I haven’t taken a gravity reading on the starter yet but I was curious what some thoughts are on topping off with the boiled/cooled water? Should I just start over?

Currently starter is on stir plate and looks normal. What gravity should I expect for a starter with 650mL of water and 1/2 cup of dme?


This is a rough guess from me, assuming your DME is 45PPG, I would put it roughly at ~1.03 OG.
A bit of advice for you, avoid putting your flask on a electric element burner because it can cause uneven heating which can weaken or shatter your flask. You should put your flask into a pot of water and boil that water to heat your flask, it is much safer for you and your flask. That noise you heard is probably the starter boiling and it kind of makes the flask jump and move about? Is that what you heard?
Also why so little DME for your starter? I use for 1 quart of water to 1/4 cup of DME and adjust proportionally if you want more. With your original 1 liter of starter and you only used 1/2 cup of DME you would get OG of 1.017 I think.
If you are using your old yeast from a previous batch, do you mean the whole yeast cake? If you are using the old yeast cake i’m pretty sure you can just pitch that onto your next batch of beer. Anyone else reading this please correct me if I am wrong, my calculations are just quick mental math and guesstimate.

Edited out a typo in first sentence.

Thanks for your reply.

  1. I tried the flask on the burner because I had seen it in the forums but I think I’ll avoid it from now on.

  2. I used 1/2 cup DME because that is what the directions said from NB and that is what I have always used. However, this is my first starter from recycled yeast. Should I use more?

  3. I divided my slurry into 4 equal parts. The yeast I pitched was just one of these jars.

Any advice is always appreciated. Thanks.

How old is the yeast? With 1/4 cake you probably are safe direct pitching within 3 weeks. If it’s 2 months old, your starter will probably be sufficient. If it’s older, you may want to make another starter after this one is finished.

Harvested the yeast last weekend from the “Jamil’s Evil Twin” which came in a little high at 1066. I thought I would make a starter to be safe. I decided to experiment with my flask on the burner which I explained already. I’ve never brewed with harvested yeast before so I want to make sure my batch for Friday is going to be safe. Should I keep what I have, make a new starter, or just pitch one or more of the 1/4 slurry mason jars?

You’d have been fine pitching just the 1/4 cake from the jar. But you did grow up more yeast so pitch all of it.

I’ve boiled wort on the stove in the flask before. But have you seen those chunks that the DME leaves behind? I like to get rid of that stuff so I know all that’s in my starter is yeast :slight_smile:

Good luck on brewday tomorrow!

All you really need is a pan to diffuse the heat when using a flask on an electric burner.

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