Unusually low F.G.

Brewed a APA last week,  O.G. came in at 1.060, checked with refractometer, and hydrometer. Pitched Fermentis Safale US 05 that I used a starter on. Yeast took off in about three hours, bubbling about every second. This continued on for the 4 days, before slowing to about a bubble every 2-3 seconds. On day 8, pressure has dropped on airlock, checked gravity and got 1.004. Seemed low so I checked with a different hydrometer and got same result. This seems low, too low. Am I missing something, or is it possible to ferment that much down from 1.060? I had them get down to 1.008 - 1.007 before but not this low?

Just wondering!

MCB

Bottling Saison, Banana Split Ale

Im not that surprised,,,that yeast is a monster.Did you have a low mash temp causing a highly fermentable wort? That would be my guess.

That's 93% attenuation.  I've never heard of anyone getting over 86% without sugar.  Did you have any simple sugars in your recipe?  How confident are you in your OG? 

Safale 05 yeast has an attenuation of mid 70% range.  This throws up red flags.  As Tom asked, did you have simple sugar like corn sugar or honey in the recipe?  And how possible is it that your OG is off?  Have you tasted it yet?  It would be possible that you got wild yeast in it.  How about fermentation temp, did it go high?

I know it doesn't add up. I've been brewing for about 8 years and never seen this. I checked the FG with 2 different hydrometers, thinking there's no way it could be that low. I hit my target OG at the 1.060, and everything was looking good. Like I said, it was bubbling fast for about 5 days. I've never seen anything lower than a 1.007 before and that was like a Kolsch. I dry hopped it and we'll see what happens. I will check it one more time.

Here's the grain bill:
#5 US Pale 2row
#5 UK Maris Otter
#1 Crystal 40
#1/2 Carapils

Thanks for the input, I'll let you know what happens.

MCB

Maplecitybrewer said:

Thanks for the input, I'll let you know what happens.

Click to expand...

Please do.  Very curious how it turns out.  Have you sampled it when you took your gravity readings?  If so, how does it taste so far?

Wow!  I've never experienced that kind of attenuation.  What temp did you mash at and for how long? Have you calibrated your thermometer lately? I've had mine drift out of calibration and read low. As a result, my mash yield was off. Just a thought..

MrBrewEsq

what was your starter gravity and how long did you do it before you pitched. If it was around 1.040 and you made a 1 liter starter then yeah it's going to go gang busters on you. but that's going to really depend on how big your starter was.

OK- I bottled the the APA, and it tasted awesome, dry hopped it with a oz of citra and a oz of cascade. Can't wait until it's bottle ready . I checked gravity again with 2 different hydrometers and it was sitting at 1.004, no change. Who knows, so unless it happens again I'll just enjoy the homebrew.  ;D  I made your basic starter, 500ml, not sure of gravity on it. I guess I should start checking that. I usually pitch starter when it's really active, (12-14 hrs) instead of letting it finish out. My lag time is only a couple of hours depending on how big of OG. I did wash and save the yeast from this batch. I figured if it turns out great, I want to try it again and see if I get similar results. So far, looks good.

Thanks for replies
MCB

Monday 6-4  After brewing again, I realize that my usual time for a starter is about 16-18 hrs give or take a hour. I put it on the stir plate around 8 PM and pitched it around 1PM the next day.

On deck: Steam, Kolsch, Rye PA 

Update: I brewed this beer again on 6/19. I gathered and washed yeast from first batch, I got a couple jars of clean yeast ( US 05). I brewed beer in the same way I usually do, mashed in at 152F the night before let sit over night and brew the next day. I got an OG of 1.059, and pitched harvest yeast, after about 4hrs I started to see some activity in airlock. The next morning it was going strong. I'll keep you posted on how it goes. I'm curious as how it will turn out this time.

BTW: The first batch was great. Nice color, had a good head that stuck around. The aroma and taste of the Citra and Cascade hops is awesome. All my friends love this beer.

It's ten days later now, airlock has some pressure on it but I haven't seen any change for 2 or 3 days. Took a gravity reading, and got a 1.006. So this is the second low FG reading on this yeast. 1.006 happens but I normally don't see it. Like I said this yeast in the Fermentis US 05 dry that I used a stir plate when making the starter. I got quite a bit when I washed and harvest yeast from first batch. I'm going to wash this again ( letting it settle out as I write this) and see what happens.

Thanks and have a Happy Forth

MCB

This may be the new "norm" for this yeast. I recently did a Blonde that started at 1.045 and ended at 1.006. That's the lowest I have ever been able to go with this yeast with nothing but grain used. I don't know why it is pulling so low, but I like the results! I have a Pale Ale going now with US-05. We'll see how it turns out for a FG.

I brewed a 10 gallon batch of American Amber Ale about 6 weeks ago using Safale US 05.  This was not my first experience with this yeast, but it seemed different during this fermentation.  While this yeast is known for its short lag phase and active fermentation, this last ferment was voracious.  All active fermentation stopped quickly after the fourth day.  At the end of week one, I transferred to a secondary.  The gravity reading was 1.009.  After another week in the secondary, the final gravity was 1.008.  It seemed odd, there was hardly any yeast settlement at the bottom of the secondary.  I bottled 5 gallons and kegged the other 5 gallons.  The bottles finally conditioned this past week; 4 weeks after bottling.