Stir/Shake/Harvest

[Broothru]

Is the bag you use a paint strainer from the hardware store?

Looks like it's Swiss Voile. I used to have my wife sew some bags back in the day when I used to BIAB. The material is a bit pricey at the fabric store, but it cleans and sanitizes easily, strains exceedingly well, is light weight but extremely strong, and is temperature stable to 350F IIRC. Great stuff.

 

[McMullan]

Looks like it's Swiss Voile. I used to have my wife sew some bags back in the day when I use to BIAB. The material is a bit pricey at the fabric store, but it cleans and sanitizes easily, strains exceedingly well, is light weight but extremely strong, and is temperature stable to 350F IIRC. Great stuff.

It does do a great job. I got a couple a few years ago and I'm still on the 1st one. In fact, I can't even remember where the 2nd one is now.

 

[marc1]

I used 800g Maris Otter (Warminster Low Colour) for no particular reason, just that the sack was open. Some brewing salts (to get a 'general' profile) and 3.5L tap water. The nylon grain bag fits nicely into steamer that came with the 4L pot (Ikea, I think).

Mashed in:



With the lid just cracked, I get a fairly stable mash temperature on the lowest hob setting. Mashed at 62℃ for about 75 minutes. As it's starter wort, I want it very fermentable, hence to low mash temp. This might be partly why yeast seem to grow better in fresh wort vs DME? More nutrients too, I guess.



Boiled for about 45 minutes outside on the grill:



I add a pitch of yeast nutrient before topping up.



Topped back up using boiling water and gave it a good stir at flame out:



Lid on and being left ('no chill') until tomorrow morning.


Obviously, if required sooner it can be chilled.

When I make a big batch of starter wort I boil it for a few minutes to get past the hot break, but not anywhere near 45 minutes.
Any particular reason you boil so long?

 

[McMullan]

When I make a big batch of starter wort I boil it for a few minutes to get past the hot break, but not anywhere near 45 minutes.
Any particular reason you boil so long?

Yes, I like to ensure the starter wort is sanitary. If I'm culturing from a loop's worth of yeast or stepping up from there (from 10ml) to 100ml, I'll simmer with the lid on the following day, a double boil, to kill any spores that germinate after the 1st boil. Malted barley is very far from sanitary. I'd boil for at least 30 minutes here, but I'm not working to a tight procedure. The boil might be longer if I'm busy doing other things. It doesn't matter, because I'll top back up anyway.

 

[marc1]

Yes, I like to ensure the starter wort is sanitary. If I'm culturing from a loop's worth of yeast or stepping up from there (from 10ml) to 100ml, I'll simmer with the lid on the following day, a double boil, to kill any spores that germinate after the 1st boil. Malted barley is very far from sanitary. I'd boil for at least 30 minutes here, but I'm not working to a tight procedure. The boil might be longer if I'm busy doing other things. It doesn't matter, because I'll top back up anyway.

I see. If you're working from small amounts of yeast, any contamination can be a problem.

I pressure can mine afterwards so that it is shelf stable.

 

[McMullan]

After diluting to get 1.040 wort I managed to get 3.5L.

Left about 300ml trubby crap in the pot.

Going back to the OP, which I feel I've hijacked a bit, any starter is better than no starter when using wet yeast, but all methods only work well when healthy, viable yeast are used. The simplest method involving just leaving it and swirling it occasionally, when you pass it, works fine. It takes 4 days or so and the cell count is going to be a little lower, but it works. As already noted, a stir plate, my method of choice, is the most efficient method for culturing yeast. It only needs to keep the yeast in suspension where they freely access sugars and other nutrients. An Atlantic style maelstrom isn't needed, regardless how impressive it might look. Two very important factors to consider when culturing yeast starters. Keep it warm, up to 30℃ is fine. The warmer it is the higher the metabolic rate. Remember it's a yeast culture not a fermentation. And aerate the starter wort. Yeast need O2 to bud efficiently. Give it a good shake before adding the yeast. If you have pure O2, use it. Pure O2 can take even a stir plate to a whole new level.

If you have a yeast pack that's passed its best and maybe not sufficiently viable for a single step starter, start with a mini starter of about 10ml wort in a 30ml vial. (Ideally, the wort at this step and the next is sterile, at least double boiled, as described earlier.)

Just add a tiny drop of the yeast slurry, no bigger than a match head. Leave for at least 48 hours, until yeast sediment forms (like above). Step up to 100ml and leave it for another 48 hours. Repeat, 500ml then 2500ml. You're guaranteed to have significantly more viable yeast cells than had you pitched the whole pack in 2500ml. The aim really is to maximise the probability of a successful fermentation, rather than take chances with the unknown.

 

[Broothru]

Great summation. The only tweak I might add would be in propagating the first step of a sample of questionable viability would be to use a wort with a gravity of about 1.020, or half strength, then use 1.040 SG worts in subsequent propagation steps. Actually I believe that a wort of 1.038 has been shown to be the optimum gravity for yeast propagation, but lower viability starters benefit from a less stressful "jump start" with weaker wort. Think of it as nursing a sick colony back to health with thin soup, then fattening it to consume a banquet.

 

[HoppyHaze]

Going back to the OP, which I feel I've hijacked a bit,

That was a welcomed hijack. This has been incredibly helpful, I just did my first starter on a stir plate and the lag time was greatly reduced when I pitched it. In fact i'm not sure how quick it took because I pitched at bedtime and it was bubbling away by morning. I plan on creating your mini mash for future starters. Thank you!