Don't believe the yeast calculator!

J A

J A

Well-Known Member
Premium Member
Established Member
Joined
Jan 19, 2016
Messages
3,878
Reaction score
3,325
Points
113
Here's the scenario: 5.5 gallon batch, 1.055 gravity, WLP810 yeast. Yeast calculator settings: Pro Brewer 1.5 (Lager), 3 (THREE!!) vials of fairly fresh (30-day) yeast.... Calculator says still need a 2-liter starter?
Really?!!
I just refuse to believe that 3 times the manufacturer's recommendation (5 gallons of less than 1.060 gravity wort per 1 vial before best-by date) is not enough.
Need to nail the fermentation because A) ...competition brew and B)...relatively schedule, so don't want to take any chances.
Thoughts?
 
J A said:
Here's the scenario: 5.5 gallon batch, 1.055 gravity, WLP810 yeast. Yeast calculator settings: Pro Brewer 1.5 (Lager), 3 (THREE!!) vials of fairly fresh (30-day) yeast.... Calculator says still need a 2-liter starter?
Really?!!
I just refuse to believe that 3 times the manufacturer's recommendation (5 gallons of less than 1.060 gravity wort per 1 vial before best-by date) is not enough.
Need to nail the fermentation because A) ...competition brew and B)...relatively schedule, so don't want to take any chances.
Thoughts?
Click to expand...

The yeast calculator ALWAYS tells me I need a TON of yeast. I've made great ales with only one vial of liquid yeast (hefe) at 1.054. - I started using the calculator and making starters (2L) and my hefeweizen got all the wrong notes! - Consistently. Went back to my old ways.

That's just my two cents. I honestly believe for most my beers - even lagers - I can get away with being under. I doubt you need a 2L starter - See what some others say.
 
  • Like
Reactions: J A
So the calculator says you need about 425B cells. On a stir plate two vials should get you enough in a 2 liter starter, or one vial in a 3 liter starter.

I under pitched a lager last year with one pac of Wyeast (100B cells) and months later we tried it - yuck diacetyl. Better to over pitch.
 
Last edited:
5 gallons of beer is 18,927 ml. I did the math: Using the Pro Lager rate of 1.5 million cells/ml/degree Plato, I get 357 billion cells required. The math checks; however, I believe the calculator is based on repitching slurry, not using fresh yeast. I'm doing a Helles tomorrow, two packets of dry yeast, rehydrated, pitched into a 2-liter starter. I don't remember the factor for using fresh yeast right off hand but I believe you can get by with quite a bit less than the calculator says.
 
I did a quick search - for fresh yeast, about half the pro brewer rate is generally good enough - but better safe than sorry IMHO. If I'm using dry yeast, I always rehydrate it, if I'm using liquid yeast, I make a starter 1-2.5 liters, depending on whether it's an ale, a lager, a high gravity beer. And for the helles, I did a 2 liter starter and two packets of rehydrated dry yeast. It's an excess of caution but I like very clean beers.
 
Nosybear said:
two packets of dry yeast, rehydrated, pitched into a 2-liter starter. I don't remember the factor for using fresh yeast right off hand but I believe you can get by with quite a bit less than the calculator say
Click to expand...
Stuck using liquid, hence the low count. Much, much rather use dry, starter or not, because the count is nearly exponentially better. ;)
Given that it's a Cream Ale using a Steam Lager yeast, I'll under pitch a little and it'll be fine. I'm just surprised in general that MFR's recommendations should vary from the real world by that much.
This will be a hybrid type of fermentation so I want to treat it like a lager to keep it fairly clean and then ramp it up fairly quickly to avoid low attenuation. Usually, I'd use a single vial to do a 2-3 gallon batch of table beer to get to a good pitch for a 5.5 gallon batch of .050 and then pitch on that to get 10-11 gallons of a 1.060 or thereabouts. This one just needs to happen quickly and cleanly. :)
 
J A said:
Here's the scenario: 5.5 gallon batch, 1.055 gravity, WLP810 yeast. Yeast calculator settings: Pro Brewer 1.5 (Lager), 3 (THREE!!) vials of fairly fresh (30-day) yeast.... Calculator says still need a 2-liter starter?
Really?!!
I just refuse to believe that 3 times the manufacturer's recommendation (5 gallons of less than 1.060 gravity wort per 1 vial before best-by date) is not enough.
Need to nail the fermentation because A) ...competition brew and B)...relatively schedule, so don't want to take any chances.
Thoughts?
Click to expand...

Another good reason to use dry yeast if available for the style.
 
I dont bother with starters anymore for my Lagers. I pitch 1 vial (Wyeast2124) per gal of wort and have activity within a few hours then on subsequent batches i reuse slurry at the pro 2.0 Lager rate on the yeast calculator for up to 12 generations before i buy new yeast so the overall cost of yeast is pretty small.

I also ferment my Lagers pretty cold at 45-48° so more yeast is better at lower temps. You can probably get away with less yeast at higher temps but you may need a D rest later on. I've probably have done a 100 or so lagers with this routine and never had the need for a D rest, always very clean and crisp, I ramp my temps down instead of up.
 
Manufacturer recommendations for pitch rates have traditionally been too low. I brew mostly lagers and often for competitions, I pitch at 2.0 per ml/degree plato for lagers. I always over pitch lagers with fresh healthy yeast and that means a starter. The advantage of a starter is you will have a very fresh and young yeast pitch that has a lot vitality. Just because you have a large number of yeast doesn't always mean a good fermentation, they need to be young to give you a great fermentation. The beers are very clean, no fruitiness so common in home brewed lagers.

I just brewed an American lager with this method, pitched wlp840 at 44F and slowly brought the temp up to 46F and had a 18 hour lag. White Labs also says the optimum temperature is 50-55F, I like it better at 46-47F. So take the manufacturer's recommendations with a grain of salt, treat them as guidelines.
 
Given the time constraints of my brewing partner in this competition, we pitched as much yeast as we could get and we'll hope for the best. ;)
 
J A said:
Given the time constraints of my brewing partner in this competition, we pitched as much yeast as we could get and we'll hope for the best. ;)
Click to expand...
It's hard to go wrong in that direction. Good luck with it!
 
  • Like
Reactions: J A
Nosybear said:
It's hard to go wrong in that direction. Good luck with it!
Click to expand...
They didn't have as much as I would have preferred...could only get 3 fresh vials. :)
We ended up brewing a double and pitching one 5-gallon batch with 2 vials to get a reasonable chance at lower-temp fermentation and the other 5-gallon batch with 1 vial to run as an ale at mid-60s temp range.
Could have just pitched all 3 on one 5-gallon batch and saved the other wort for a different purpose but this seemed like a good way to see what the yeast would do and have 2 beers as potential entries.
 
J A said:
They didn't have as much as I would have preferred...could only get 3 fresh vials. :)
We ended up brewing a double and pitching one 5-gallon batch with 2 vials to get a reasonable chance at lower-temp fermentation and the other 5-gallon batch with 1 vial to run as an ale at mid-60s temp range.
Could have just pitched all 3 on one 5-gallon batch and saved the other wort for a different purpose but this seemed like a good way to see what the yeast would do and have 2 beers as potential entries.
Click to expand...
Looking forward to hearing about the results!
 
  • Like
Reactions: J A
Nosybear said:
Looking forward to hearing about the results!
Click to expand...
Should be an interesting beer. The conceit of the competition is that the ingredients are chosen in a Fantasy-League-style draft....Base malt, yeast, hops, specialty grains and you have to brew using exactly those ingredients. We chose good stuff to work with - Pilsner, Corn, Aromatic malt plus Cluster, Simcoe and Mosaic hops. We could have chosen from some various ale yeasts but the WLP810 yeast offered more versatility. We brewed a Cream Ale/Pilsner Blonde with a craft-beer kick of hops in the whirlpool. It'll be fun to see how it turns out, especially with the different pitch rates and different fermentation temp/schedules.
 
J A said:
According to recommendations on the site and on the vial of WLP810, 5 gallons of 1.048 wort would be fine for 1 vial. The calculator calls for 4 vials to avoid having to make a starter using those specs.
Click to expand...

No- look at what they recommend for lagers and cold pitching.
 
  • Like
Reactions: J A
Yes, that^^^. :)
 
J A said:
Should be an interesting beer. The conceit of the competition is that the ingredients are chosen in a Fantasy-League-style draft....Base malt, yeast, hops, specialty grains and you have to brew using exactly those ingredients. We chose good stuff to work with - Pilsner, Corn, Aromatic malt plus Cluster, Simcoe and Mosaic hops. We could have chosen from some various ale yeasts but the WLP810 yeast offered more versatility. We brewed a Cream Ale/Pilsner Blonde with a craft-beer kick of hops in the whirlpool. It'll be fun to see how it turns out, especially with the different pitch rates and different fermentation temp/schedules.
Click to expand...
What a kick ass idea! I hope you do well! Fill us in on the results and how the beers compare.
 
  • Like
Reactions: J A
You must log in or register to reply here.
Copyright © 2007-2024 Brewer's Friend, Inc. - Send Feedback - Terms - RSS Feed - Do Not Sell or Share My Personal Information

Back
Top