Yeast starters

[Ian Grant]

How important are they??

I'm not worried about lag time unless it hurts the flavor of the beer. I'd rather just pitch it out of the pack.  I managed to get a 1L pyrex flask is that big enough?  Is it best to use DME or is dextrose good enough.   I know I could find most of this on HBT but it's probably good to have the topic on this forum too..

Ian

[Shawn]

Very.

While it's been said a lot, it really can't be overstated how important yeast health is to the final beer product. Sure, if you pitch a smackpack into some 1.060 wort, it may eventually take off and seem fine, but if you don't want to stress the yeast, and really want to do whatever you can to come out with the absolute best end-result, yeast starters should always be used, when necessary, for liquid yeast.

Some starters need to be quite large, so I doubt a 1 L flask will be enough; at least, not in all cases. You ideally need some head space, just like in your primary fermenter; when a starter is active it can achieve a good head of foam, especially when you give it a swirl.

Don't use corn sugar (dextrose); using that in a starter will greatly diminish the yeasts' ability to ferment the complex sugars that you find in wort. Definitely use DME, or saved wort from your sparge if you all-grain brew. You want a starter with a gravity of 1.030-1.040 for fresh to relatively-fresh smackpacks.

I'm sure you've heard of the yeast pitching calculator at mrmalty.com. Use it, it's a big help.

[Ian Grant]

Ok instead of the flask what should I get to do the starter?  I didn't know about that site but I'll check it out.

Thanks

Ian

[Shawn]

I was lucky and found an old one-gallon glass jar at work. I know some people use 2 L Erlenmeyer flasks.

Anything large will probably work, that can be sanitized.

Others on here may be able to throw in a few more ideas...?

[Richard]

In the book "Yeast" they suggest that for most beers, a single-step from the smack pack into a 1.5L starter at 1.036 (so 1.030 to 1.040) is generally a good rule of thumb, and will double 100 billion cells to about 180.

The same book gives the formula for ale pitching as (which since it's written in part by "Mr Malty" we can assume is behind his calculator):

0.75 million x milliliters of wort x degrees plato of wort

So an ale with an OG of 1.048 (12 plato), for 23L, you'd need:

750,000 * 23000 * 12 = 207 billion.

Assuming you're only doing 5.5Gal/21L you're looking at 189 billion. If you raise the plato to 15 for 21L you "need" 236 billion... etc etc. I personally don't buy into the exact numbers produced. Giving a formula like this is somewhat misleading as the innoculation rate (750k for ales) is clearly subject to strain and the flavour profile desired. Moreover I'd be willing to bet that yeast's reaction to wort density is not as linear as the formula suggests. This just gives you a sensible target to start with, which should avoid a majority of pitching-rate related off-flavours.

Various (off-)flavours exhibit at over- and under- pitching.

Health (vitality) is as important as quantity (viability) of yeast. If you've got a bunch of bud-scarred, shocked yeast with weak membranes you're opening yourself up to all kinds of fail. A starter is intended to increase both vitality and viability.

Make sure you either use a stir-plate or shake-stir the thing manually as often as you can, as the dissolved oxygen levels are important to producing healthy growth.

As for the flask, you want something that can withstand heat-shock to some degree -- putting the thing in a preheated oven with a little water inside it and some tinfoil on the top seems to be the way to go. Don't try and crash-cool anything glass, even borosilicate.

[Shawn]

I use the method of bringing the water needed to a boil in a saucepan, add the DME, boil for about 10 minutes, then cool in a cold-water/ice bath.

When it's down to low to mid-70s, I then pour the wort into a sanitized vessel (I sanitize with Starsan, just like any other brewing equipment) and add the yeast.

There's lots of videos on youtube, if you would prefer real demonstration, which helps.

[Ian Grant]

This is great info guys.  I stopped by the lab at work and found some empty chemical bottles that should be perfect.

[Kyle]

The bottles are glass right? Plastics are absorbent and therefore not good for this application

[Ian Grant]

The bottles are glass right? Plastics are absorbent and therefore not good for this application

Yeah they are..   Clear glass growler bottles that they just throw out when its empty..  If anyone is interested I can't see a problem with me taking all I want and I can bring them to the meetings.  They take a #5 bung..

[Dave Savoie]

I would love a few If you could give them to either Kyle or Richard and I will pick them up next time im in the city !!!

[Gil Breau]

I would love a few If you could give them to either Kyle or Richard and I will pick them up next time im in the city !!!

Tag one on for me if you can get them for Dave and I'll grab it from him

[Richard]

Aye just chuck as many as you can spare my way and I'll get them to people.

[Kyle]

Good find Ian...

I'll take a couple if you don't mind.  I can also hold on to Dave's for him.

[Dave Savoie]

http://a4.sphotos.ak.fbcdn.net/hphotos-ak-snc6/207259_1971681814492_1316415634_32305836_7697742_n.jpg

[JohnQ]

Would love a couple to.
Thanks,
JW