My efficiency tends to be consistently low for my big (>1.080) beers), so members here have suggested I’m not pitching enough yeast. Using a stir-plate, Mr. Malty says I need 366mm cells @ 1.4L using 2 vials of WLP007 for my next stout. I double checked the calcs and I agree based on:
Last week I made the first starter and put it in the fridge for 4 days. Monday night I decanted that, made a 250ml starter, and poured that into the flask. I’d say the cake is around the 500ml line on the flask now, with barely any liquid noticeable. Is that all there is to it? Such a small amount of sugar from the second step is all that’s needed for the yeast to get to the target number?
So first, efficiency has nothing to do with how much yeast you are using. Efficiency in brewing is a measure of how much of the available sugar you are extracting from the grain.
Now, if you meant Attenuation, then that can relate to pitching rates.
I don’t think you got much from the 250 ml step really. I will make a 1 liter starter for 1 vial of yeast but that’s about as small as you want to go with a starter. What Mr Malty was suggesting was that you make a single 1.4 liter starter and pitch two vials into it.
Generally I make ~1liter starter and pitch a vial of yeast into it. If I need more (according to an online calculator like you used) I might step that up to a 2 liter starter after its done. although there are many who say this does not do much good cell count wise.
That being said I don’t think you have 500 ml of solid yeast. But it will be fine if you crash and decant the clear ‘beer’ before pitching. I suspect you will end up with more like 50-100 ml of yeast slurry tops.
What most people mean when they talk about stepping up a starter is doubling the size of the starter at each step.
I will sometimes decant my 1 liter starter and add a fresh liter of wort. I’m probably not getting as much yeast growth, but whatever. It’s worked for me just fine.
On occasion, I’ll use a growler to make a larger starter.
If I were you, I’d make that second step a whole liter to get as much yeast as possible for a big stout.
As for attenuation, sometimes big beers just need time even with an appropriate pitch of yeast.
Geez, yes, I meant attenuation, not efficiency. My OG’s are usually where I expect them to be, but my FG’s constantly stall around 1.040 and I’ve been told I’m not pitching enough yeast.
So in your opinion, Norther Brewers’s guide isn’t too useful? I had a feeling a 1/4 L wouldn’t really do much. I’ll take your advice and add another 1L into the flask.
Regarding the time, I’ll let it ferment in the primary for 5 weeks, then straight to the bottle, then I won’t drink for at least months… if I’m patient.
If I try to diagnose the problem of poor attenuation it would only be for my benefit, ie trying to confirm what I’ve learned along the way.
From the clues in your post, I assume you brew all grain, because you refer to efficiency. So we know your OG is 1.080ish, and your FG is way too high. I would need more info to diagnose the problem. Such as your recipe so we would know the expected fermentability. Your mash temps, aeration method, type of yeast, and temp at which you ferment.
Are you brewing extract, partial mash or all grain? Mort and the others are spot on of course:) There are a lot of variables pertaining to attenuation, especially if you are brewing AG.
Aeration is also a biggie as that’s what the yeast need once they hit the wort! Otherwise, freshness of ingredients, mash temps, etc come in to play…
BTW, you mentioned 1.040 as where they are sticking? That’s pretty high, are you by chance using a refractometer for your FG readings? IF so, I suggest using a calibrated hydrometer. Even with proper conversion refractometers are less than reliable when confirming FG readings.
Edit: Jim got some of this in before I finished typing:)
Everyone’s suggestions are great but I do want to note that when using a refractometer and using standard conversion formulas I have seen variances of ±.002 or .003 from a hydrometer test but not .02. Being off that far is usually someone not doing the conversion math correctly (or not at all). You can do what you like but the refractometer saves me time and ±.003 is close enough for my needs. No need to scare people away form useful tools.
Sorry, not trying to scare anyone away from useful tools, it’s just from my experience that many aren’t aware of the need to convert or don’t do so properly or use calculators that aren’t that reliable so I wanted to point it out:)
The recipe says to mash @ 148 for 90 minutes and to pitch WLP007 @ 68. I use an aquarium pump for 5 minutes (overkill?) to aerate. And yup to all grain and a refractometer. A few points here and there is good enough for me… but clearly 1.040 indicates something is wrong during my process.
14.40 two row
2.00 flaked oats
1.54 chocolate malt
0.93 15L crystal
0.90 black malt
0.90 roasted barley
0.82 carapils
I’m seeing a lot of lowered attenuation grist in that recipe. Couple that with it being a high gravity and I would think it’s possible some of your problem is that. I’d scratch the carapils. That recipe doesn’t need it. But I doubt that would be the magic bullet. Just part of it.