OG and FG were off a bit? How to hit target next time?

[lorne17]

Hello there,

I bought Brewers Best Irish Stout Extract kit and brewed it 3-2-13. Then I bottled last night 3-22-13.

The Original Gravity was supposed to be between: 1.046-1.050 and the Final Gravity was supposed to be between: 1.011-1.014. My OG was 1.040 and my FG was 1.020. So my ABV was only 2.75%! It's supposed to be 4.2%?

I used this calc: (OG - FG) x 131.25 = ABV%

The fermentation was done after 20 days and I don't think that FG was gonna change any. It's bottled now and it tasted good

What would you guys suggest to fix this next time? I'm gonna be brewing a Cream stout (and will probably add coffee/vanilla) next month and want to get it more accurate.

Thanks,
Lorne

 

[unionrdr]

Make sure when you top off to recipe volume in the fermenter that you stir roughly for 5 minutes to aerate it a little & get the chilled wort mixed well with the top off water. That's what I do to get an accurate reading.
You likely didn't get them mixed well enough.

 

[lorne17]

Hrmmm good suggestion. I remember I didn't aerate a ton for my last amber and it's very sweet. I aerated this quite a bit.

My primary is a 5 gallon carboy so I get a lot of blowout. Woult that be part of the culprit?

I also was in primary for 3 weeks.

Thanks,
Lorne

 

[BlackRock]

Your OG should be pretty spot on using extract once you get your volumes worked out. Are you doing a full or partial boil? I'd agree that your OG could be both a measurement problem if the water you added didn't get mixed into solution thoroughly first. It will also lower your OG if you had to add too much water to the fermenter. So getting your volumes dialed in with extract brews will help you hit your target OG.

As for the FG that's really dependent on the yeast. The 5 gallon carboy shouldn't be causing any issues during fermentation even if you do get a bunch of blow off. It's more a question of yeast health and good pitching rates combined with ferment temps and aeration of your wort.

Make sure your wort is cooled to the proper temp, aerate the wort so you've got enough Oxygen in it to help the yeast get started and make sure you pitch some healthy yeast. You also need to make sure your beer is stored at a good temp for the yeast, so if it's too cold they may slow down so much they'll take forever or stall out.

What strain did you use the first time? You may also think about doing a yeast starter if you go bigger with your next beer.

 

[unionrdr]

No,the blow off wouldn't change the gravity. Volume maybe. How did you aerate?

 

[lorne17]

Thanks for the replies.

My yeast for the first two batch were Wyeast pack, and white labs liquid yeast. The Stout was a dry yeast that I hydrated and everything looked fine and worked fine. It started fermenting in 12ish hours. And fermented ALOT more than my Amber did.

I do a full boil of 5 gallons and had 2 boil overs (luckily it was my first time outside so not a big mess) and had to add about 1 to 1.25 gallons in and then I shook it up to aerate before pitching the yeast. The wort was about 70F and I brought the yeast down to about 80F before pitching it. The fermentation runs about 62-64F in my basement. Colorado winters in unfinished basement. But as warm weather is coming, that will go to high 60s I bet.

Maybe I need to double check where 5 gallons mark is in my carboy again, I thought I had it figured out right at the point it turns towards the small top hole. Do you recommend I switch my primary to a 6.5 gallon carboy? Then use my 5 gallon for a secondary? What's the benefit of that?

Thanks for your input,
Lorne

 

[realdadshangout]

My primary is a 6.5 and secondary is a 5 and I don't have blow offs. I did when I used a 5 bucket

 

[unionrdr]

The 5G is intended to be used as a secondary you need a fermenter of 6.5 gallon size to have the proper head space for 5 gallons of beer.

 

[logan3825]

If you are doing extract you really don't need to take an OG reading. As long as you hit your volumes and know how much extract you used you should hit your OG.

 

[unionrdr]

I know they say you don't need to take an OG,but I like to be thorough. Good to know how a particular batch is doing for future reference.

 

[logan3825]

Why bother taking a reading if it is likely to be inaccurate anyway? You know your extracts. You know your volume. You can calculate your OG from that. It is almost impossible to get things mixed up in the fermenter. Seems like a waste of time to take an OG reading.

 

[unionrdr]

Why bother taking a reading if it is likely to be inaccurate anyway? You know your extracts. You know your volume. You can calculate your OG from that. It is almost impossible to get things mixed up in the fermenter. Seems like a waste of time to take an OG reading.

No,not at all. It isn't that hard to mix top off water with chilled wort. I do it all the time the way I said to do it. Some times it's a bit higher,sometimes lower. Particularly when not using kits,although they can react the same way.

 

[lorne17]

Well if I didn't take the OG I wouldn't know if I was this far off. I mean 2.75% when it should be 4.2% is pretty far off!

Yea I think I'm getting another 5 gallon soon as a gift. I may upgrade that to a 6.5 gallon.

Thanks,
Lorne

 

[logan3825]

Well if I didn't take the OG I wouldn't know if I was this far off. I mean 2.75% when it should be 4.2% is pretty far off!

Yea I think I'm getting another 5 gallon soon as a gift. I may upgrade that to a 6.5 gallon.

Thanks,
Lorne

You probably got a bad measurement.