1272 Starter fail, Stir Plate newb

[Nodrog]

So first time using the stir plate, and not a great outcome.

Pretty sure i know what i did wrong, but surprised it was this bad!

I use a 3litre Erlenmeyer, makes 1.5 litre starter coming close to boiling over. Process:

Weigh 150g of DME into flask
Reset scale to zero and weight in 1.5kg hot water
This measures way over 1.5litres on the flask scale, but i presume weighing is more accurate than flask marks.
Put in stir bar.
boil 10 minutes with foil over lid.
cool in sink with cold water
Pitched about 50mls of yeast slurry from previous*
Onto stir plate for 48 hours.
Think this is where i went wrong. I planned to use it after 3 days, but change in plans, did brew day a day earlier.
The starter smelt great, bready, little bit citrusy which apparently 1272 can, but clean.
Took it off plate and let yeast settle for few hours. It settled into what i thought looked like a good slurry of yeast, 100+ mls?
The 'beer' tasted ok, but FG = 1020, not fully fermented
Pitched the starter into 23 litres of SG1035 wort.

3 days later no activity, SG not moved. Gave up and threw in 2 packs of S04.

Fail. I'd have thought 48 hrs would be time for some good activity / growth / multiplication / yeast party whatever they do?


*previous: I opened a pack1272, used 3/4 of it in a brew (which went great), and grew a starter from the rest. Didn't have the stir plate then, but let it grow for 3 or 4 days shaking whenever i walked past it. Let it settle out, poured off the beer, and kept the slurry in the fridge for 2 weeks. Think i used about1/4 of the slurry from this starter in the next one.

 

[HBHB]

The slurry you used, was it thick or watery?

Did you wash the slurry from the bottom of a fermenter and split into several batches then drew off 50ml?

Need a clearer picture.......can't tell if you're washing the yeast or just dragging slurry across to the next batch.

If i'm washing yeast, I usually do it with about 2 L of pre-boiled water and swill it around well, allow to settle. drag off the cleaner part of the liquid and re-wash with a total of about 2.5L of pre-boiled (cool) water, that then gets split into 4 x 500ml bottles which get stored at 2 deg C until needed. They get a shake up, warm gently to room temp and pitched into a starter and stir plated with a sanitised foil cover for 24hrs if in 1 L and 48 hrs if in 3 L.

Have rarely bothered doing further generations personally.

Martin

 

[Nodrog]

The slurry came from a previous starter, it was really thick.
I'd let the 1st starter fully ferment out, let it settle for 12 hours or so, and poured off the 'beer' from the top.
Gave it a swirl, and poured that slurry into a sanitised jar that I kept in the fridge for 3 weeks.

When I made up this starter i gave the jar in the fridge a good swirl, as it had settled out further, and poured in around 1/4 of the total from the previous starter. I didn't let the jar warm up as I was planning on using a 1/4 of the jar. The idea was that I'd get 3 or 4 brews from the fridge jam jar without going through multiple generations.

One of things i'm needing clarification on is how much is a 'cup of slurry' or 100mls of slurry, etc. It surely depends on how longs its settled for, how well its been washed of other sediment, and how diluted?

 

[HBHB]

I would imagine a "cup" is 250ml as a metric measure.

I'd (just me anyway) be splitting the batch into smaller amounts of a single pitch so that you're not risking contamination every time you open the jar to get another serve of yeast.

 

[TidalPete]

Are your scales accurate? I would like to think that the markings on an Erlenmeyer flask coming from a laboratory type place would be pretty true.

Pitched about 50mls of yeast slurry from previous*
Onto stir plate for 48 hours.

Sounds like everything has gone ok so far but what volume of starter wort was added to the 50ml? How was it stepped? A simple thing like forgetting to sanitise the outside of any vessel could kill yeast dead.
Perhaps let starter settle out, discard surplus wort & then add 1\1.5 litres of fresh wort from the (Cooled) OG wort on brewday to make an active starter & add to FV when krausen starts? Aerate well.

Consider using bleach (Re-use afterwards to save the world) instead of boiling in the Erlenmeyer.
Then sanitise.
This will give you much more volume per flask -- EG: 1.5 litres\2-litre Erlenmeyer depending on the yeast.
Hope this helps?

Edit ---- Only going by your previous post (1) as am in & out of computer ATM. Cheers.

 

[bradsbrew]

Of course 150g of DME + 1.5L of hot water is going to read more than 1.5L in the flask. How cool was the wort before adding the slurry?

 

[Nodrog]

Starter Wort felt 'cool', similar to Auckland tap water temp in winter. Not sure want to use a thermo in boiled sterilised wort? Starter was fermented in ferm fridge at 20c.

Re cup/ w250mls etc, yes am comfortable measuring the volume, but the definition of 'slurry' seems vague to me, just how thick / runny / diluted is it?

Happy to be shown wrong, but am confident the starter prep went well. Just difficult to believe the starter, 1.5 l of it, half way through a healthy ferment wasn't enough to kick off the 20litres or so.