So I was wondering about the Wyeast smack packs. Is it already the starter or do you have to use it to make a starter with it? I know with dry yeast you should make a starter but I have just poured it in to my bucket and carboys. I haven't used liquid yeast yet so this is all new to me. Plus to reuse the yeast afterwards do you have to make a starter then?
Wyeast Smack Packs
- Thread starter TomWaggle
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stratslinger
Well-Known Member
You've kind of got that backwards... Let me explain. 
With dry yeast, most people don't make starters. It's cheaper (in terms of ingredients and time invested) to simply pitch multiple packets if you need it. You do, however, typically want to rehydrate your dry yeast prior to pitching. I don't remember the exact mechanism behind this, but suffice it to say that a dry yeast packet contains about 200 billion yeast cells, and if it's pitched directly into wort, up to half can die before the propagation phase of fermentation takes hold. Properly rehydrated yeast doesn't see this kind of die-off. That 200 billion cells is also much more stable over time - a 60 month old packet might have 190 billion cells (maybe more), because dry yeast tends to die off very slowly if properly stored.
With liquid yeast, when packaged a smack pack or vial contains roughly 100 billion cells. So automatically, you're pitching less cells than you would be with dry yeast. And liquid yeast is less stable, over time, than dry. After 6 months, that 100 billion cells has died off to just about 5-10 billion (it's why White Labs vials have expiration dates on them that are, coincidentally, 6 months after the packaging date). Smack packs are not starters - they're just packages of yeast with a little nutrient that is supposed to prove to you that the yeast in the pack is alive before you pitch it. But, since it starts dieing off pretty much as soon as it's packaged, it really needs to be pitched into a starter to get the cell count up to where you need it prior to pitching into your wort. And, since smack packs are pretty expensive, making a starter is much more cost effective with liquid than it is with dry yeast.
Clear as mud?
With dry yeast, most people don't make starters. It's cheaper (in terms of ingredients and time invested) to simply pitch multiple packets if you need it. You do, however, typically want to rehydrate your dry yeast prior to pitching. I don't remember the exact mechanism behind this, but suffice it to say that a dry yeast packet contains about 200 billion yeast cells, and if it's pitched directly into wort, up to half can die before the propagation phase of fermentation takes hold. Properly rehydrated yeast doesn't see this kind of die-off. That 200 billion cells is also much more stable over time - a 60 month old packet might have 190 billion cells (maybe more), because dry yeast tends to die off very slowly if properly stored.
With liquid yeast, when packaged a smack pack or vial contains roughly 100 billion cells. So automatically, you're pitching less cells than you would be with dry yeast. And liquid yeast is less stable, over time, than dry. After 6 months, that 100 billion cells has died off to just about 5-10 billion (it's why White Labs vials have expiration dates on them that are, coincidentally, 6 months after the packaging date). Smack packs are not starters - they're just packages of yeast with a little nutrient that is supposed to prove to you that the yeast in the pack is alive before you pitch it. But, since it starts dieing off pretty much as soon as it's packaged, it really needs to be pitched into a starter to get the cell count up to where you need it prior to pitching into your wort. And, since smack packs are pretty expensive, making a starter is much more cost effective with liquid than it is with dry yeast.
Clear as mud?
flars
Well-Known Member
when you harvest yeast from the fermentor a starter, for the harvested yeast, is not necessary when the yeast is used within a few weeks. Remember viability decreases each day after production.
I like this calculator for pitch rate and starter size. (You may have noticed a thread on the development of a new calculator. Looks very, very good. I just haven't worked with it yet.)
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/
Hope one finger typing isn't confused you.
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