Not hitting my gravity

[tegeberg]

Hi guys

Today I was brewing up a partial mash tripel and i ended up waaaay low on OG. Fermentables were as follows:

3 kg pilsner (mashed)
1 kg dextrose
0.5 kg of light dry extract

From my calculations (and hopville) this should yield 13 l of 1.089 wort at a mash efficiency of 65%.

After my mash I had 12 l (3.2 gallons) of 1.04 wort. Having mashed 6.6 pounds of grain (2.06 pounds pr gallon) this should give me an efficiency of 54% giving that pilsners max PPG is probably like 36 or so (max = 2.06 x 36 = 74. Efficiency = 40/74 = 54%) . That is a lower efficiency than calculated, but not an aaaawful lot under.

After adding the dextrose and DME at flameout and topping up I ended up with 13 l of 1.074 wort (yes, temperature was taken into consideration) .

My question is, how the hell can I have hit 15 gravity points below my target? My hydrometer should be at least almost correct as it gives the correct gravity for water etc.

Any help will be greatly appreciated.

Cheers,
Thomas

 

[Jklinden]

My inclination is that unless the wort was stirred very thoroughly the extract may have separated by density giving a false hydro reading but that is just a guess...

 

[bottlebomber]

My inclination is that unless the wort was stirred very thoroughly the extract may have separated by density giving a false hydro reading but that is just a guess...

That's my guess. I have seen at least a dozen "my gravity is low!" threads in the last month, and every time it was someone topping off. Just topping off and swirling or shaking the fermenter isn't enough to mix the solution, the thicker wort will persist at the bottom.

 

[tegeberg]

Ok, so if this is the case, will it mix itself up in the fermenter and will there be any impact on the final product? Can I calculate my OG from the 54% efficiency and assume that it is correct?

 

[bottlebomber]

Ok, so if this is the case, will it mix itself up in the fermenter and will there be any impact on the final product? Can I calculate my OG from the 54% efficiency and assume that it is correct?

It will mix if that is the issue without any negative effect. You can't calculate an accurate OG unless you are sure that is the issue though. Do you have another fermenter you could rack it back into? This would give it a nice aeration and would surely mix it. This might not be the problem though. Did you do a conversion test for your mash? Sometimes pilsner malts can be undermodified. This means they may need more time than 60 minutes to convert all the starch to sugar. Also I didn't quite understand your process. Did you sparge? What is your setup like?

 

[tegeberg]

I am aware of the problem with my efficiency as such. I believe it is mostly due to heat loss and my problem with keeping a constant temperature. But I am absolutely positive on the 1.040 reading after the mash (at 3.2 gallons), so how that could have ended up 3.5 gallons of 1.074 after adding 1 kilo of dextrose and 0.5 kilo of DME I do not know. I am right assuming that this is WAY too low right?

Can anyone of you think of other potential problems than the mixing?

Thanks for the help btw, it is greatly appreciated.

 

[bottlebomber]

It sounds like you're getting poor efficiency from your system. Are you doing BIAB? A mash tun? What temp did you mash at and for how long? If it was BIAB, did you sparge?

 

[tegeberg]

Yes, it is BIAB. And I did sparge. My mash temperature was constantly between 140-150, mostly in the high 140s. I loose a lot of heat though, so I regularly add boiling water.

 

[MTB]

OP I had the same problem on my PM and I have no idea why.

That's my guess. I have seen at least a dozen "my gravity is low!" threads in the last month, and every time it was someone topping off. Just topping off and swirling or shaking the fermenter isn't enough to mix the solution, the thicker wort will persist at the bottom.

Would transferring the wort between 2 buckets six times mix the solution enough?

 

[bottlebomber]

OP I had the same problem on my PM and I have no idea why.

Would transferring the wort between 2 buckets six times mix the solution enough?

Yes, this should definitely mix the wort thoroughly, and also give a pretty good aeration

 

[tegeberg]

So if I have two buckets, do you suggest siphoning the wort between the two before taking gravity reading or simply pouring the whole thing from one to another giving a good splash?

 

[MTB]

So if I have two buckets, do you suggest siphoning the wort between the two before taking gravity reading or simply pouring the whole thing from one to another giving a good splash?

I pour the wort between 2 buckets six times to aerate and mix. I've never had a problem reaching FG this way. However, I did my first PM this week and missed my starting gravity by 13 points. No clue why it was so low too.

 

[bottlebomber]

I pour the wort between 2 buckets six times to aerate and mix. I've never had a problem reaching FG this way. However, I did my first PM this week and missed my starting gravity by 13 points. No clue why it was so low too.

What it your mashing system?