I've a smack pack dated september2012 of wyeast 3068(weihenstephan strain). I've been trying to calculate what size starter I need(not something that normally bothers me but as a matter of interest). Mrmalty tells me I need 7 smackpacks and a 1 litre starter and I've 10% viability and yeastcalc tells me I need 1 pack in a 2 litre starter and I've 1% viability. I'm using a stirplate. See screen grabs of 2 calculators below. Can anyone explain the 'huge' discrepancy for me please? Am I using them correctly??
Thanks!
Mr Malty always seems to generate more questions than answers :(
Keep it simpler, was that the production date or expiration date?
If its the prodction you are fine to pitch directly as per instructions.
If its the expiration a very simple rule of thumb is one day for every month that you are over so min six days on the stir plate, consider 2 goes at it, so a 500ml batch, settle 8-12 hours in fridge, decant, and a 1 litre to get it really back to full viability.
http://www.wyeastlab.com/hb_makingastarter.cfm
Thanks CH, that's production date and I read somewhere that it'll need a starter after about 6 months. I'd still really like to understand the calculators? Anyway I'd rather slightly over pitch because I don't like my hefes to be overly strong on the banana and apparently under pitching brings that out more with this strain. Also, is decanting a starter a good idea with a low floc strain like this as surely I'm just keeping the highly flocculant yeasts?
Thanks !
Wyeasts are ok up to 6 months, pop it and watch how quickly and big your bag fill out?
I'm with you I always try to marginally over pitch to make sure I get a solid start to fermentation, so just go with a 500 ml starter?
I use beersmith and also app on the iPhone, the calculators are fairly wysiwyg.
If you want to know the detail, bed time reading ;)
https://www.homebrewersassociation.org/attachments/0000/1235/MAzym07_YeastStarter.pdf
Thanks CH. I'm going to read that PDF. I actually have the yeast book but I'm quite haphazard about my starters. I usually have plenty of viable yeast but like to waken them up with a small starter. However, I intend figuring out what's going in with those calculators!