New brewer - low OG

Hi there, new brewer here. I have brewed twice now, with the second being yesterday when I brewed two batches. I am using NB extract w/grain kits. I did Irish red for the first two and Nut brown for the third (second yesterday). I have many questions, but the first and probably most important is: “Why are my OG’s low?” I brewed the Red following the directions with two changes. Instead of starting with 2.5 gallons, I started with 3 gallons. The second change is that I didn’t bring it to 5 gallons because the OG was 1.034. It is supposed to be 1.044. The next brew was the Nut Brown Ale, again I began with 3 gallons and found 1.035. This time I did bring it to the 5-gallon mark. I figured I would see what difference it would make and it came down to 1.030. Again, OG was supposed to be 1.044.

So, the burning question is what could I have done wrong? What can I improve? Incidentally, reading this forum looking for answer to this I found brew outdoors and do a full five-gallon boil. I am using a turkey fryer to brew. Should I just do all 5 gallons right up front?


If you’re brewing extract, and you use all of the extract and end up with five gallons, your OG will be correct. You’re experiencing stratification of the wort–it can be pretty difficult to get the top up water thoroughly mixed in. After my first few extract brews, I realized that taking an OG reading was totally unnecessary . With extract, you only need readings to determine if you are at final gravity.

Doing 5 gallon boils and brewing outside will not effect your OG. If you can do a five gallon boil, it will help the color of your beer, but you might have to alter the hop schedule because you get better hop utilization in a full boil.

Sounds like you are taking a gravity reading before top up. How are you measuring gravity?



Welcome to the forum, jdkay!

I agree 100% with Frenchie that stratification is most likely why your SG measurement is off. As long as your measurements are accurate it’s pretty hard to miss the expected OG with extract kits. And yes, it would be better to do full volume boils.

Gravity readings are highly temperature dependent. If you measure when the wort is still warm at all, the reading will seem very low. You need to measure at 60-70 F for accuracy.

Thanks for the replies. Some more information.
a) I made the mistake of reading How to brew by Palmer before doing a few brews. Now, I worry about the cautions and concerns that would never have occurred to me. OMG, the pot is aluminum! Nothing I can do about this for the time being.
b) I am using a refractometer with automatic temp correction (supposedly, anyway). I am well within the range for the device. After I posted here, I found the stratification answer on another forum (Home Brew Talk - Should have Googled first).

  1. Now, that’s leads to the question of what affect will the low volume have on the red? I was using a borrowed carboy for this one and it has no volume markings. I estimate that I am between ½ to 1 gallon short.
  2. The reason I was using the additional volume (although small) in the boil was because I had read that this would improve the color and the hop utilization. Where can I find the how to alter the additions?
  3. On an unrelated note: the directions say: Add yeast once the temperature of the wort is 78°F or lower (not warm to the touch). The borrowed carboy, the red, didn’t have a fermometer. After brewing the nut, I realized that not warm to the touch for me was still quite warm. Will this have a detrimental effect? Why does the T matter except to avoid killing the yeast?
  4. Both brews were bubbling like mad by before 24 hours. Now at 48 they have slowed considerably and the krausen has fallen. Should I wait the seven days or 24 hours after it has fallen, as I was advised by someone?

Thanks again for the help

Just a few answers from me here:

  1. I brewed in an aluminum kettle for a while and had no detrimental effects. I believe a lot of us still do.

  2. A pitching temp of 78* is pretty high. A warmer wort will make for a faster fermentation, and adds to the possibility of off flavors, depending on the yeasts tolerance. In the future, get the wort temperature down as close to the yeasts temperature range as possible. What I do is cool down the wort using an ice bath to around 60-62* for ale yeasts. I’ll pitch and use a swamp cooler to control the temp for a few days. A simple design for a swamp cooler is to use a tub and fill it with about 4-6 inches of water, then drape a towel or shirt over the fermenter. Leave that fabric in the water a little so it will “wick” up the cool water. I have a fan blowing on mine to keep the temps down even further. This is good for a few degress under ambient easily.

  3. Question: Are you making sure to use ALL of the liquid/dry extract for each batch? 1.034 seems very low compared to what it should be. Make sure to rinse any liquid extract jugs with warm water to get it all.

  4. if you had a volume of 4-4.5 gallons in the fermenter of 1.034 wort, then you will end up with a similar amount of beer, minus trub/hop debris loss. If it’s FG gets to 1.010 you’ll have a 3.15% ABV beer.

Temp does have to be pretty hot to kill off all your yeast. You may stress them though with a higher temp, leading to the off flavors mentioned above.

I try to pitch all my ale yeasts at about 60 degrees, then let it rise to my fermenting temp from there. Gives it a nice and easy start. It can be tough during summer to get the temp that low with my IC, so I may even seal up my carboy with sanitized foil and leave it in my freezer for a while. Once I notice it is at about 60 degrees, I take it out and toss my yeast in.

Also, as mentioned above, it can be tough to get every single bit of extract out. That could lead to a little bit of a lower gravity reading, but not a whole lot. It’s more likely the wort stratification. Common issue with extract.

With extract, I would always try to do a full volume boil if you have a large enough kettle. You should estimate about how much you’re going to boil off over the hour (you can test this with just straight water if you want, it’ll be close), and then add that to how much volume you want total. It might be around, say 6.25 gallons. For extract, you’re always going to have a slightly darker beer than with All Grain. Not much you can do about that. You can do full volume boils and add your extract closer to the end of the boil (at about 15 mins) to try to help that, but in my experience it doesn’t help all that much.

As for waiting and how long to wait… just wait. When you think you can’t wait any longer, wait longer. :smiley: The yeast will continue to clean even after visible signs of fermentation have stopped. When I brew, I usually start my day with it. I’m pitching sometime in the afternoon. I’ll continue to check it that night and sometimes the next morning (if it’s a little slow) to make sure fermentation started. I pretty much leave it for a week after that. Then I’ll check again to see if it’s still active. If not, I let it sit another week before I sample it (unless I see something I’m not sure about). If it’s still active, I let it sit longer. You’re not going to hurt anything by letting it sit for a couple of weeks to finish out. If you bottle too early, you could wind up with bottle bombs and they are bad.