Low OG, FG...what went wrong?

Hi - I'm a newbie that just finished bottling my first batch today.

I have a question though: on the "kit" I used (which was created/assembled from my lhbs) the target OG was 1.048. Mine turned out to be 1.036. Target FG was 1.012, mine was 1.018. I waited longer to bottle than the instructions said (I had closed fermentation, and based on my reading that seemed to be ok). My beer was in a carboy for almost 3 weeks.

Based on the calculators available online, my beer is going to be pretty weak from an alcohol % standpoint. I can live with that, however I'm wondering what I might have done wrong that created such a low OG. Also, should I have left the beer in my primary longer? I was afraid to thief out some beer and do a hydrometer test before bottling...I didn't want to risk contaminating it...perhaps I was too timid first time out.

Oh well, it's not the end of the world. I would like to get a clearer understanding of what might have happened and how to avoid it on my next batch...

Frankly, I'm relieved it tasted okay. So far, it isn't ruined.

Thanks for any thoughts ya'll can provide.

First, how much water did you end up with in your primary fermenter? That will affect the OG. Most of us shoot for ~5.5 gallons in the fermenter on a 5 gallon batch as you'll lose some to trub and the how high the siphon is off the bottom.

Congrats on waiting a full 3 weeks, most of us are more impatient that that on our first batch =)

I usually drop a sterilized hydrometer into the primary when I'm siphoning (racking), no harm there.

CouchFarmer said:

First, how much water did you end up with in your primary fermenter? That will affect the OG. Most of us shoot for ~5.5 gallons in the fermenter on a 5 gallon batch as you'll lose some to trub and the how high the siphon is off the bottom.

Congrats on waiting a full 3 weeks, most of us are more impatient that that on our first batch =)

I usually drop a sterilized hydrometer into the primary when I'm siphoning (racking), no harm there.

Click to expand...

When I racked it to my bottling bucket today, it was about 4.5 gallons. Looks like I didn't add in enough additional water after the boil...

If you have too little water your OG should be higher than estimated, not lower. You didn't describe your process so I can't guess how much wort you had at the end of the boil and how much you lost in transfer from brew pot to primary, and primary to bottling bucket, etc., but you should be in the right ball park there.

How much grain was there, what was your process for steeping it? If your temperature was low or too high there you might not have gotten enough sugars out of the grains. A simple steep should be in range of 150-175 F.

Another possible culprit is your extract, it may be old or lower quality.

For your FG 1.018 is a little high, but not too far off. What was your pitching temperature, did you use liquid yeast with a starter or dry yeast?

Over all though, if you get decent, drinkable beer on your first batch it's cause to celebrate - RDWHAHB. Every time I brew I tweak my process a little bit, your beer will get better with each batch.

CouchFarmer said:

If you have too little water your OG should be higher than estimated, not lower. You didn't describe your process so I can't guess how much wort you had at the end of the boil and how much you lost in transfer from brew pot to primary, and primary to bottling bucket, etc., but you should be in the right ball park there.

How much grain was there, what was your process for steeping it? If your temperature was low or too high there you might not have gotten enough sugars out of the grains. A simple steep should be in range of 150-175 F.

Another possible culprit is your extract, it may be old or lower quality.

For your FG 1.018 is a little high, but not too far off. What was your pitching temperature, did you use liquid yeast with a starter or dry yeast?

Over all though, if you get decent, drinkable beer on your first batch it's cause to celebrate - RDWHAHB. Every time I brew I tweak my process a little bit, your beer will get better with each batch.

Click to expand...

Couch Farmer - thanks for the encouragement. I kept reminding myself about Charlie's advice.

Here are your answers:
1. Water and wort lost on xfers, etc: Xfers went well, not much left behind except for the stuff you "want" to leave behind. I had previously boiled, then frozen in sanitized containers 1 gal of water. I added 1 previously boiled, then refrigerated in sanitized container 1 gallon of water. I used those (along with ice bath in sink) to cool my wort after boiling. I started with 3 gallons. (My pot wouldn't safely hold more than that...it's only 4 gallon total capacity.)
2. Grain: Total of 5 oz. (2 of carafa choc malt, 2 of brit crystal 30-07L, 1 of black malt). Instructions were to bag it, place in water, then slowly bring to 155 degrees over a period of 40-60 minutes. It took me 63 minutes to get water to 155. Then instructions were to remove grain bag. I didn't pay serious attention to the grain so I can't say conclusively if I needed to roll it, but they did look cracked.
3. Extract: can each of Sun Country Light, Cooper's Light. The LHBS I purchased from is pretty popular, but I'm obviously not an expert on quality or how fast their inventory turns.
4. Yeast: Liquid yeast, started 6 hours before pitching. Wyeast London III that was between 69-70 in my basement. However, I got overenthusiastic on my wort cooldown (the ice/water additions mentioned above and ice bath)...when I took my OG reading the sample's temperature was 64 degrees...so the yeast might have been shocky getting pitched in to much colder liquid. My basement stayed between 69-71 during the whole 3 weeks it was in the primary.

Thanks again, Couch Farmer!

kcpup:

It's surprisingly hard to mix high-gravity wort after boiling and top-off water. It takes a lot of stirring. It's really common to end up with a heavy layer of wort at the bottom of the fermenter, and a lighter layer of water with some wort mixed in at the top. This leads to low OG readings.

If you hit your initial volume (which is a really important measurement for extract brewing), and used all the extract/sugars/grains in the kit, you should be reasonably close to the stated OG, even if your measurement technique is off.

jds said:

kcpup:

It's surprisingly hard to mix high-gravity wort after boiling and top-off water. It takes a lot of stirring. It's really common to end up with a heavy layer of wort at the bottom of the fermenter, and a lighter layer of water with some wort mixed in at the top. This leads to low OG readings.

If you hit your initial volume (which is a really important measurement for extract brewing), and used all the extract/sugars/grains in the kit, you should be reasonably close to the stated OG, even if your measurement technique is off.

Click to expand...

+1 on this explination. It was probably a skewed initial reading.

I know this is an old thread, but I stumbled across it while doing a Google search for figuring out why my FG readings were so unexpected. One thought that I'd like to add is what are the chances that the original poster forgot to do a temperature adjustment for his hydrometer? It took me several batches before I consistently remembered to adjust my hydrometer readings from the measured temperature to the calibrated temperature (60 degrees).

Just thought I'd add that thought in case someone else came across this thread.

Hey Gomer I hear ya..

I think I had to take a long hard look at how I used my Hydrometer, especially in a liquid that could have different layers, and on top of that correcting for temp. Hell I thought i knew what the hell I was doing,every time i brew i am reminded that i do not.:rockin: I had a hella low OG and i tried to eep every last point out of the secondary FG...and after 3 weeks I went from a 38 to a 18.....aww damn guess im drinking the oatmeal stout just for the flavor...brew number two (strawberry blonde)on the way...bubbling like a bat out of hell for 3 days so far...well on its way to a happy FG that will give about 5.5 ABV.