Stir Plate Flocculation?

[Robbienev]

Hi All,

Got my starter going yesterday afternoon. 2 cups water, 1/2 cup DME and a smack pack of 1968.

It's been on the stirplate overnight and now looks like there's a lot of yeast clumps formed.

My question is should I just keep it on the stirplate until I pitch this afternoon or should I pop the flask in the fridge right now and pull her out an hour or so before I pitch?

 

[flars]

i would keep it on the stir plate until pitch time. this will ensure that it is done fermenting, and have it a pitching temperature.

 

[MrSnacks]

It's 1968, that stuff drops like a rock. I'd stick it in the fridge and then decant the liquid before pitching.

a .5L starter is really pretty tiny though, why did you make such a small starter?

 

[Robbienev]

Thanks for the info folks.

So one for leave it, one for fridge it - anyone wanna help break the deadlock 😃

The small starter is mainly my inexperience (2nd all-grain batch here we go) but this will be a low gravity bitter so all should be fine.

I will however double up on the starter next time.

 

[trentm]

OK, here is an option. If you feel the propagation has reached terminal gravity, take it off the stir plate and leave at fermentation temperature for 8 to 12 hours. According to the book "Yeast", the culture will build up its glycogen reserves during this time. High levels of glycogen are a great advantage to yeast culture. Since this is a highly flocculating strain the need to cold crash may not be necessary. However, if decanting, be sure all the yeast have settled. Because this is a flocculant strain if you decant before complete settling, you will not get the less flocculant cells which may be very important with this strain. Since you have such a small starter, IMO, it won't hurt to pitch the entire starter.

 

[Robbienev]

Yeah, I figured pitching the whole starter would be fine.

I do think that she's done with fermentation (no more bubbles in the airlock) but I'm going to be pitching in about 4-5 hours so maybe letting it keep on spinning is best?

 

[trentm]

Yeah, I figured pitching the whole starter would be fine.

I do think that she's done with fermentation (no more bubbles in the airlock) but I'm going to be pitching in about 4-5 hours so maybe letting it keep on spinning is best?

In his book, Chris White is not clear (the way I read it) about whether or not to keep spinning after terminal gravity is reached. Here is my opinion: The main purpose of a stir plate is to keep a constant supply of O2 to the culture and secondly to remove CO2 (some will debate the order of importance). After terminal gravity, more O2 could be detrimental as no CO2 is being produced. Since you are using an airlock, I think no harm is being done by continuing to spin.

BTW, a foil cover, or a cotton or foam plug is recommended for yeast propagation as an airlock will not allow for gas exchange. Don't worry, it will not cause aeration problems in your beer. But you may not want to keep spinning after terminal gravity.

Here is a link to some really good information on yeast propagation: http://www.maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

 

[kh54s10]

Advice:
.
1) Look at online calculators to determine the proper size of a starter for a given beer.
2) get a scale and weigh your DME. Volume is very inaccurate.
3) ditch the airlock. Use sanitized foil over the top. The yeast need oxygen to propagate.
4) 18 - 24 hours on a stirplate is usually sufficient. I find that it takes overnight to cold crash or all day so it depends on when you need to pitch the yeast.

For that small of a starter I would let it go to get as many cells as possible then pitch the whole thing.

 

[Robbienev]

Really appreciate all the advice, it's awesome to have a resource as rich and deep as this forum.

Thanks all, and cheers,

Robbie