All grain, high final gravity, help please

[dfouty]

Hey guys,

I hope you guys can help me out because I'm being driven crazy here. I have been extract brewing for about a year and recently switched to all grain brewing. I had a bad thermometer the first brew and didn't hit mash temps so I got a new one.

Second and third batch seemed to go perfectly. I hit mash temps and the gravities before fermentation.

The problem is that each fermentation ends up with a gravity of about 1.030 which is just way too high. The first beer was around 1.064 and the second was about 1.068 original gravity. I made a 1 liter yeast starter for each one. And the fermentation seemed normal. They were both fermenting for about three weeks and the gravity hadn't changed for the last week.

Can someone point me in the right direction? I'm getting really sad that all grain isn't working out yet and I'm doing another new brew soon. If it happens again and it's at 1.030 can I just throw in another yeast starter and finish it off?

Any help would be great. Thank you for any help.

Cheers,

Dave

 

[Btaz]

My guess is that your fermentation temp is not under control. I had a batch that finished poorly and then turned into bottle bombs because my fermentation temps were out of walk.

 

[Skiffy]

Some more info would help.
Grain bills?
Mash temps?
Yeast?
Fermentation temperatures?
How are you measuring FG?

 

[Qhrumphf]

Are you measuring FG with a refractometer? Because that'll explain it right there. You can't use a refractometer for readings after you've pitched yeast without correction, because alcohol disrupts the reading. Either use a hydrometer, or a calculator to correct the refractometer reading. 1.030 consistently screams this problem.

Now, if you're using a hydrometer, I'd look to a couple things-

-Is your hydrometer calibrated (ie reads 1.0000 in water at reference temperature), and are you correcting the readings for temperature?
-What thermometer are you using, and what's your mash-in procedure? You may be getting hot spots or inconsistent temp.
-What mash temp(s) are you using?

And then the usual questions, yeast strain, recipe, fermentation temps, etc.

My guess if you're reading accurately via hydrometer, the thermometer you're using isn't as accurate as you think it is. I had a thermometer that was accurate at boiling and accurate at freezing, but was off in mash range. I had the opposite problem with over-attenuation, and found my thermometer i thought was accurate was reading about 5 degrees high in mash range- when I thought I was mashing at 152 i was mashing at 147. If yours goes the other way and you think you're at 152 but you're at 157, that can be your problem right there.

 

[day_trippr]

Make this easy:

- Post the recipe of the latest brew that finished high.
- Let us know what the mash temperature profile was.
- Tell us how you measured SG and FG.

The answers should pop right out...

Cheers!

 

[Singletrack]

I would guess fermentation temperatures were too low or dropped near the end and caused a stall. You could try increasing ferm temperatures as the activity slows.

If you haven't already checked your hydrometer in water, do that to make sure your 1.030 reading is correct. Should read 1.000 in distilled water at the reference temp of your hydrometer, typically 60 F.

 

[Black Island Brewer]

Let's start with the refractometer answer, and go from there. 1.030 would be wicked high even if you messed a dozen things up.

 

[dfouty]

Hey guys, thanks for all the quick replies. I'll have to get back to you on the exact grain bill but the yeast was Wyeast American Ale both times and the fermentation temp was around 64-70. Mash temperatures started at about 155 and dropped to 152 by the end of the mash.

I measured all the gravity using a refractometer. I've never heard of having to correct after pitching yeast. Can someone explain?

 

[Black Island Brewer]

Hey guys, thanks for all the quick replies. I'll have to get back to you on the exact grain bill but the yeast was Wyeast American Ale both times and the fermentation temp was around 64-70. Mash temperatures started at about 155 and dropped to 152 by the end of the mash.

I measured all the gravity using a refractometer. I've never heard of having to correct after pitching yeast. Can someone explain?

Alcohol throws off the measurement with a refractometer. There are supposed calculators, there's even one built into BeerSmith, but the general opinion is they are not really reliable.

You might want to check the fermenting gravity with a hydrometer instead. You may be closer than you think.

 

[dfouty]

Just did some research on post fermentation readings with refractometers. That is the problem! Thank you guys so much! Seriously have made my night!