Attenuation question

I have a question regarding attenuation percentages on extract brewing. I have made two batches so far and am only getting rates of 65-68%. My first started at 1.069 and finished at 1.021 and I used us-04 yeast. My second batch strated at 1.074 and finished at 1.024 and I used us-05 yeast. I have a chiller and pitched my yeast around 65ish degrees and splashed my wort back and forth to get oxyen in it both times. My first batch had active fermentation signs within 12 hours and the second didnt sart showing signs until 24 hours. I did not use a starter either time. I am expecting to get rate of 75- 80%. Thoughts?

Could you post recipes? Did you do a full boil? Or late extract additions?

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My first was the kit from Midwest, the Furious IPA clone. I followed the directions exactly. Here are the ingredients. The extract was added all at once and boiled for 60 minutes. Assuming hop schedule doesnt apply to the issue. I did a full boil and only topped off to get to 5 gallons

•6 lbs. of Gold liquid malt extract
•3.15 lbs. of Amber liquid malt extract
•4 oz. of Crystal 50-60L
•1 oz. Warrior
•2 oz. Amarillo
•2 oz. Simcoe
•1 oz. Ahtanum hops

Second was one I made up. Added the 3.3 pilsner liquid extract late; 35 minutes into the boil.

7 lbs. Light liquid extract
3.3 pilsner liquid extract
1 lb of crystal 20 steeped at 155 for 25 minutes
.5 lbs of crystal 10 steeped at 155 for 25 minutes
4 ounces of Columbus hops a varying times throughout the boil
2 ounces of Columbus- dry hop

Thanks for you help.

I can only think of aeration as an issue. I've used both 04 and 05 and find they preform well. How vigorously do you shake? Before I bought a wine degasser i did it manually and rolled my glass Carboy back and forth on my deck. I would shake the F out of it and try and get tonnes of foam inside. You know your doing a good job when you can see tiny tiny bubbles rising to the surface. If you are shaking it back and forth inside a bucket that ain't enough. Unless the lid is on. But then you need to open the lid periodically to let fresh air in. Good luck.


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Thanks I will try that. I normally do this by spashing it back and forth between and bucket and my kettle a couple times and then pour it into the carboy. I always strain it once too. It has always been foamy after doing this too so I assumed I had enough air in it.

Some brewers say you don't need to aerate with dry yeast. I do anyway because it will not be detrimental to the yeast if it is not needed.

The OG of the two brews you mention are at the point of requiring greater than one package of dry yeast. One and a half packs may have taken care of the high finish.

You also said you followed the instructions to the 'T'. Did the instructions say to transfer to the secondary after four or five days of fermentation?

I did follow it as stated in the directions. Directions indicated to move to secondary, keg for me, to dry hop after 5-7 days of fermentation. I did move it after 7 days and I had stable gravity reads on my hydrometer for two straight days. I will try more yeast next time. Is there a OG starting point where more yeast is required?

did you rehydrate the yeast, or just pitch it directly on top of your wort?

did you secondary? if so, when did you move from primary?

cardfan said:

Thanks I will try that. I normally do this by spashing it back and forth between and bucket and my kettle a couple times and then pour it into the carboy. I always strain it once too. It has always been foamy after doing this too so I assumed I had enough air in it.

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I have no idea then. Seems like it should have been enough aeration. Did u leave your beer in primary for long enough. 10 days???


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I'm far from an expert on these things but it seems to me that even at the higher gravities a single packet of yeast would be enough. Considering in every batch that you pitch dry yeast it has to go through some serious reproduction before it can start the active fermentation. But I guess if fermentation started before the yeast population was large enough to consume all the sugars quickly the resulting alcohol content could be too much for the yeast?

What it seems to me like is you transferred too soon while fermentation was still going on and may have stalled it. Or since you said you had consistent readings two days in a row what temp were you fermenting at? If it was too cool it could have stalled it as well.

Just throwing out my ideas and opinions. Someone please correct me if I'm wrong, especially on the yeast.

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I've done a 1.070 with 1 packet of yeast. Beer attenuated properly.


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I was going to say too much extract in too small a boil causing unfermentalbe sugars and while that still may be the case for a couple of gravity points. I'm now leaning to racking too early and staling fermentation. Maybe try warming just a bit and giving your keg a swirl to get the yeast back up into suspension. I'm not an expert, so hope it helps.

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cardfan said:

I did follow it as stated in the directions. Directions indicated to move to secondary, keg for me, to dry hop after 5-7 days of fermentation. I did move it after 7 days and I had stable gravity reads on my hydrometer for two straight days. I will try more yeast next time. Is there a OG starting point where more yeast is required?

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Take a look at MrMalty. Punch some different OGs in there for the calculator results. Compare these results with the calculator at Brewers Friend.

I don't use dry yeast to often. My cut off point for using a single 11 gram pack of yeast is 1.060.

I would also leave the beer in the primary for at least three weeks. I bottle, so at three weeks the beer has dropped clear. Also gives the yeast time to clean up off flavors produced by the fermentation.

m1batt1 said:

I'm far from an expert on these things but it seems to me that even at the higher gravities a single packet of yeast would be enough. Considering in every batch that you pitch dry yeast it has to go through some serious reproduction before it can start the active fermentation.

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every time a yeast cell splits, it is giving half of itself - its skin (membrane), its guts, etc - away. so yeast can't reproduce indefinitely. eventually they run out of stuff to give away and still make a viable cell. typically a yeast cell can create about 4 new cells before being too weak to split again.

use a pitching rate calculator, like http://www.mrmalty.com/calc/calc.html, to figure out how much rehydrated yeast to add (it's important to rehydrate!). mr.malty says that 1.3 packets is required for 5.25 gallons of 1.074 wort, so 1 packet isn't ideal but it's probably close enough. if you don't rehydrate, 1 packet probably isn't enough since many (Jamil says up to half) of the cells will die due to sugars and other things rushing inside the cell walls. 0.5 packets instead of 1.3 is a big difference, and that might explain attenuation issues.

On the first batch, no. I moved it to dry hop in my keg after 7 days (2 days of gravity reading that were the same). This second batch is still fermenting and I am dry hopping in my primary this time. I will check and see what my gravity is at the end of dry hopping before moving to a keg. Maybe this one will go down a little from the 1.024 it is currently sitting at. Thanks for your responses I am happy with my beer taste so far, just looking for better results in this specific area.

Thanks, that is great info. I will try the calculator on my next round. I think in the future, given a similar OG, I will use more yeast or make a starter. Twice in a row is enough to make my try something different.

cardfan said:

I think in the future, given a similar OG, I will use more yeast or make a starter.

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make a starter only if you use liquid yeast. dry yeast is best rehydrated, but don't make a starter.