Mysterious starter problems

[Noetikon]

I am relatively new to (all-grain) brewing but have done around 40 batches so far. I finally built a stir plate for making starters with liquid yeast. I know making a starter should be relatively simple, but I have had two failed attempts.

The problem is utterly mysterious: made both starters carefully following the steps outlined in the Yeast book; very shortly after turning on my stir plate, the whole thing turned into what can only be described as curdled milk (video here: http://www.youtube.com/watch?v=SExMJbYB ... re=mh_lolz.) That chunky material swirling around in the starter is definitely yeast, and it did this within 15 minutes of turning on my stir plate. For the whole 36 hours there were never any signs of activity (no krausen, no foam, no bubbling, nothing). And the gravity remained unchanged (1.040 confirmed with hydrometer). So I know that nothing happened at all.

As far as I can figure, the problem is that the yeast is flocculating almost immediately after hitting the wort (which I cooled to 73 F first). This has happened twice (one with Cali V and one with WLP007), so I know I'm doing something wrong. Both ‘curdled’, both failed to produce any visible signs of activity, and both failed to ferment *at all*. I am utterly puzzled as to what is going wrong. The yeast shouldn't flocculate almost immediately after being on the stir plate?! And surely I should have seen *some* activity. But nothing. Just 'curdled milk'.

Could my stir plate be the problem (e.g. spinning too fast and damaging the yeast??). Could it be bad DME? Or something in the water that is causing the yeast to flocculate immediately? I brew with city water, which is very good. And it hasn't caused any problems before. But perhaps something in the reaction between the water/flask/stir bar??

**Here is some additional information: happened with two different yeasts; both were fresh (expiry date two months away); yeast was smooth and uniform in the vial; no funky smells from the starter (smelled like yeast); cooled wort to 73 F before pitching; sanitized everything with Star San.

[Ozwald]

Both of those strains can be pretty chunky, nothing to worry about there.

How fast are you spinning it? All you need is to see a slight dimple in the surface - the idea is just to keep them moving, not see who can finish 10 laps the fastest. My guess is that you're getting fermentation (have you tried checking an FG) but you're spinning the surface hard enough to get rid of the bubbles before they have a chance to form noticeable foam.

[Noetikon]

Both of those strains can be pretty chunky, nothing to worry about there.

How fast are you spinning it? All you need is to see a slight dimple in the surface - the idea is just to keep them moving, not see who can finish 10 laps the fastest. My guess is that you're getting fermentation (have you tried checking an FG) but you're spinning the surface hard enough to get rid of the bubbles before they have a chance to form noticeable foam.

I confirmed with a hydrometer reading after 36 hours that there was NO gravity change (FG was identical to OG). And I know my hydrometer is working (just checked a black IPA that finished at 1.010).

I know that these are chunky strains, but they shouldn't turn chunky right from the start, should they? But since there was no gravity change, it's definitely not working.

[BDawg]

Are you adding a campden tablet to your water to remove chlorine?
A whole tablet is enough to treat 20 gallons and will kill your yeast.
You only need to use a TINY amount - 1/80th of a tablet - to treat 1 liter.
That's about impossible to measure. I'd suggest just filtering through a Brita filter instead, or treat a larger amount but only actually use a liter out of it (or 2).

[brewinhard]

Are you 100% sure your thermometer is calibrated? If it is off and you pitched your yeast over 80F then there is a good chance you may have killed the yeast upon pitching. Just a thought as I cannot think of any other reason why your gravity did not change. Pretty annoying either way...

[Noetikon]

Are you 100% sure your thermometer is calibrated? If it is off and you pitched your yeast over 80F then there is a good chance you may have killed the yeast upon pitching. Just a thought as I cannot think of any other reason why your gravity did not change. Pretty annoying either way...

Thanks for this. I have a Thermapen that I just got back from being repaired (screen issues). So I think it is accurate. Since the yeast was flocculating almost straightaway, I assume it is still alive (dead yeast don't floc). If there is no other explanation, I'm going to assume my OG reading was off (my FG was done with a hydrometer).