FG Too high - Dried yeast no starter

Hi,
My last two batches of partial biab have come out with a final gravity about 5 points above the expected could this be due to the fact i used dried yeast with no starter? My mash temps where kept low so i dont think that is the issue. Any advice on how to do a starter with dried yeast?

Could have been your yeast, could have been a lot of things. Five points isn't that much in the grand scheme of things. Are you re-hydrating the dried yeast before pitching it?

You don't need to do a starter with dried yeast because the cell count is high enough to inoculate a 5 gallon batch unless you're doing a really big beer. So unless you're buying old yeast that has had a significant decrease in viability, I wouldn't suggest going to the trouble.

I havent been rehydrating the yeast, is this necessary?

The only questions I'd have are what kind of OG's are we talking about, what kind of ferment temps, and are you sure of your mash temps?

Depending on your OG, you could still be under pitching with a single pack of dry yeast.

If you're fermenting too cool, the yeast could be flocculating before it's done fermenting.

If your thermometer isn't properly calibrated, your mash temps could be higher than you think they are - if you haven't already done so, check it against ice water and boiling water and make sure it measures 32f and 212f, respectively.

I hope you don't mind the piggy back but any advice on bringing it down those extra points? Because I was about to post a similar question except I'm about 9 points above where I should be which brings my "session" beer down to about 3.9%, not where I want to be. Been in primary for 10 days, same FG reading for 5. Unseasonably high temperatures last week, I'm sure was the issue.

I've tried rousing the yeast with no results. I'm thinking maybe racking to secondary and siphoning some of the yeast over with it, or maybe leaving it in primary until my other brew using a very similar yeast is in secondary and racking this one over to that yeast cake.

It was a 1054 OG finnished at 1020 supposed to be 1014ish.

Pretty sure of mash temps it never exceeded 150F according to my thermometer! Perhaps 2 therms next time to keep an eye on the calibration.

mikesmith1611 said:

I havent been rehydrating the yeast, is this necessary?

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http://koehlerbeer.com/2008/06/07/rehydrating-dry-yeast-with-dr-clayton-cone/

There is at least some evidence (discussed in the above link) that not rehydrating your yeast will result in the destruction of the cell wall for about 50-60% of your yeast when pitched into room temperature or colder wort (no telling how many will be able to recover over time). You need about 200 billion yeast cells to inoculate a 5 gallon batch of average gravity ale and, conveniently enough, each 11.5 gram packet of active dry yeast contains almost exactly that much. However, if you lose 50% of it because you didn't rehydrate, it's certainly possible that underpitching could be a problem.

Again, though, going from 1.054 to 1.020 is still 63% attenuation, which is low but not distressingly so. It sounds like you need to start narrowing the issues by rehydrating your yeast in about 100 degree water for about 15 minutes and seeing if that helps. Even if it doesn't help your attenuation, it's still a good practice and you can continue to look elsewhere to try to diagnose your attenuation issues. If it's not cell count, then it is almost certainly temperature - simply because those are the two main drivers of fermentation.

Thanks for the advice will hydrate next time and see if that helps

And don't assume anything about your thermometer!!! Use the procedure I described above and check it before you brew again - go into the brew knowing that 1) your thermometer is good and accurate, 2) your thermometer reads high or low by x degrees and know to correct every reading for that, or 3) toss it and replace it with a good one before you brew again!

Cheers!

Partial batch BIAB? Did you use extract. I have read that it is fairly common for extract to finish around 1.020 with no ill effects.

Yes, check the thermometer. Also check your hydrometer in distilled water to make sure it is reading 1.000. Also make sure you are taking gravity readings at the calibrated temperature for your hydrometer, usually 60 degrees.

im sure rehydration helps, but ive never done it and never had a stuck ferment from it. i highly doubt its the cause here esp in a beer where 50% viability isnt much of an underpitch. which yeast did you use and whats your grain bill look like?

SkinnyPete said:

Unseasonably high temperatures last week, I'm sure was the issue.

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if anything, the higher temps would have helped. need a bit more recipe info to help. you could try the racking idea, sometimes the added oxygen gets it going again, but its not the best method.

Maybe you could shake the carboy.

I use US-05 regularly and it always ferments to the target range for me. One thing I do is after I add the wort to the carboy, I put foil over the bung hole and rock the carboy around for a good 10-15 minutes. This aerates the wort in preparation for the yeast. Then I pitch it and put the foil back on. Once the yeast are going crazy, I put the airlock on.

You could try re-pitching.

If its already mostly fermented out, the last thing you want to do us to shake the fermenter. Unless you LIKE the taste of wet cardboard.

kh54s10 said:

Partial batch BIAB? Did you use extract. I have read that it is fairly common for extract to finish around 1.020 with no ill effects.

Yes, check the thermometer. Also check your hydrometer in distilled water to make sure it is reading 1.000. Also make sure you are taking gravity readings at the calibrated temperature for your hydrometer, usually 60 degrees.

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Ive been doing as close to AG i possibly can with my set up with each batch using about 20% extract.

If consistently higher than expected, then perhaps mash at a lower temperature. Have you calibrated your thermometer? Check that boiling is indeed 212F/100C.

And +1 to NOT shaking it at the end. Same with re-pitching. I don't want to sound mean, but that is really bad advice and is only good with a stuck fermentation, not one that stopped a few points from desired.

And as for using extract, it is common to see anything with extract finish higher than expected. Perhaps do a full AG recipe, if need be do a lower OG recipe or just a 3 gallon batch (your 7.5g fermenter will still be fine). That way you can see if it is indeed the extract.

Tall_Yotie said:

And +1 to NOT shaking it at the end. Same with re-pitching. I don't want to sound mean, but that is really bad advice and is only good with a stuck fermentation, not one that stopped a few points from desired.

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I recant that advice.

stratslinger said:

If its already mostly fermented out, the last thing you want to do us to shake the fermenter. Unless you LIKE the taste of wet cardboard.

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There's nothing wrong with "rousing" the yeast. In fact it's pretty much required for many British strains. If you have a good airlock, the headspace in your fermenter is pretty much 100% CO2 and there's no risk of oxidation.

For the OP, there's much debate on rehydrating yeast, but even if it resulted in an underpitch, that wouldn't cause a stuck ferment in a normal gravity beer. What were your mash temps, fermentation temps, and yeast strain? Also, if you're doing BIAB, are you maintaining your mash temp with a burner or by insulating the tun? If you're using direct heat, I'd make sure to stir constantly. It might be possible that you're getting portions of the mash hot enough to neutralize the enzymes before the finish breaking down the long-chain sugars.

In regards to re-hydrating and pitch rates; re-hydrating just prepares the yeast for fermenting making it start faster. It does not increase the cell count.

I have done both and did not see a big difference.

gr8shandini said:

There's nothing wrong with "rousing" the yeast. In fact it's pretty much required for many British strains. If you have a good airlock, the headspace in your fermenter is pretty much 100% CO2 and there's no risk of oxidation.

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Agreed on rousing - but there's a difference between rousing and flat out shaking. One is a gentle swirl or three to get the yeast back in suspension, the other, well, could be interpreted, especially by a new brewer, as picking up your fermenter and shaking the crap out of it, which could introduce some risk of oxidation if your setup isn't quite ideal.