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wondering if yeast health, mash temp, or mash duration could be an issue with low attentuation after one week in the fermenter, or am i checking/posting prematurely? last week i brewed edwort's bee cave rye ipa as my first all grain batch, using biab method. recipe's og: 1.064 and i hit 1.067 – I converted the recipe using The Calculator. to this wort i pitched 1.5 cups of yeast slurry from an american brown i bottled the same day. yeast was safale us-05 and that beer sat in the primary for 1 month. it's og was 1.058 and finished at 1.016 –– very close to the recipe). i racked that to bottling bucket and swirled up the last bit of slurry then poured 1.5 cups into a sanitized measuring cup, covered, and set it aside until pitching.

the brewday went well, recipe mashed for 70 min but i did 90. i mashed in at 155 and at the end of 90 minutes it was at 150, but the first 30 minutes or so it was at 154. i stirred every 15––20 minutes and the temps seemed consistent at different spots in the mash. after boiling i chilled to about 69 and pitched the slurry. i frothed the $@*& out of the wort toward the end of the chilling and then halfway between racking to fermenter i pitched the yeast, and shook up the fermenter to aerate more. then racked the remaining wort and shook it up again. finally i put her to rest in the swamp bath where she's sat in 66––67 degree water. visible fermentation occurred within 36 hours, and a nice thick krausen lasted for maybe 3––4 days with lots of bubbling before it started to fall back in.

so i'm now at 8.5 days from pitching the yeast, and about 7.5 days from visible signs of fermentation. the bubbling has slowed significantly but there are still a few bubbles each minute. the surface now is mostly cleared up but there is a thin layer of yeast still on top. the temp has raised up to about 70 in the bath.

yesterday, i checked the gravity and it was at 1.023 ... recipe's fg is 1.010. i wouldn't be surprised if the gravity came down another point or two, but it seems like 10––13 points is a long way off at this point.

yes, my thermometers and hydrometer are accurate – i've tested them. the hydro sample did not taste sweet. so i'm wondering if i am checking this too early after about a week, or if i should alter this process for next time.

i usually rehydrate/proof dry yeast, but forgot to proof this yeast slurry. i guess i didn't think about proofing it, but considering it was basically dormant yeast, i suppose i should have added some boiled sugar water to wake it back up before pitching.

i did not do a mashout, and pulled the bag by hand and added the additional drippings to the kettle at the start of boil.

thoughts about the low attenuation?

Good Day LaserGhost,
You had a pretty high O.G. and the 90min. at 155F mash will give you a lot of Higher density sugars.

Nothing to worry about. I have to secondary for 4-8 weeks until the beer is nearly clear, and I have found my 1.026 s.g. will be down to 1.012 s.g.

It seems the yeast have to learn how to eat the Density Sugars.

Laserghost
I am not an expert on attenuation. I normally only take a gravity reading prior to adding the carbonation sugar to the brew, so basically 2-3 weeks after pitching - taking readings in-between stress me out too much. But I have been thinking about attenuation recently (due to another post on the forum) and the figures behind it.

If you bear with me for a moment I might give you some perspective (and hopefully some of the experts on here will correct me if needed!).

I've done a quick search and it seems as if the attenuation for Safale US-05 is anything from 73% right up to 90%?! 73%-80% seems to be "normal".
I've done another quick search and got this formula to determine the attenuation: [(OG-FG)/(OG-1)] x 100. It looks kinda correct .

Using the formula in a spreadsheet and using the figures from your brew I've got the following results:

1. Current situation (OG = 1.067. FG = 1.023) = 66%. It does seem a bit low for the yeast.

2. FG based on recipe (OG = 1.067. FG = 1.023) = 85%. It's very much at the upper end of the scale for the yeast, but probably do-able.

3. Aim for lower end of this yeast attenuation (OG = 1.067. FG = 1.018) = 73%. It seems at this might be a possible scenario for your brew, especially if you think that there is still some sugar munching activity taking place.

4. Aim for higher end of this yeast attenuation (OG = 1.067. FG = 1.013) = 80%.

As I said, I was hoping to provide some perspective to your "problem". It doesn't seem as if you are that far off the ballpark attenuation for the yeast.

Cheers,
Lambert

thanks, joshua and lambert, very helpful info. according to palmer, i don't have a "problem" unless my fg is only a half of my og. at least i've already surpassed that, and i think i will end up with something delicious.

it does seem like perhaps i just need to give it some more time, and with a beer this size, perhaps give it a few more weeks before even taking a reading – like you say, 2–3 weeks, instead of 1.

in the meantime, i need to educate myself more thoroughly on mash temps and durations to know what affect that will have on the finished product.

On that brew, the formulas result in a predicted FG of 1.017 - 1.019 so as lambert said you aren't too far off the mark. To achieve 1.010 you'd need a yeast that attenuates to 85% which is massive! Never give too much respect to recipe reports as they often contain incomplete or faulty info.

There are a lot of factors that affect attenuation. If you are interested in this there is some good info here and here.

Step mashing, not mentioned in the links above can also increase attenuation.


PP