Can Fermcap S decrease Hydrometer reading?

[ajansen34]

I just finnished brewing what I thought was going to be a 1.070 IPA and my hydrometer reading only came in at 1.050.

6# Northern Brewer Rye extract
3# Muntons Light DME

5 gallons.

So I don't know what gravity contribution the NB Rye extract gives. I estimated to be same as Amber extract, and 0.020 difference doesn't seem right. So I'm wondering if 10 drops of Fermcap I added before taking reading might have something to do with it. My hydrometer is pretty accurate on many other recent batches, If anything it reads slightly high, not low. And I've used Fermcap in other batches, but only during boil. In the current batch I used in boil and put additional 10 drops after cooling because this is a bigger beer than I normally brew and didn't want to have a blow off tube.

I did a quick test in the hydrometer tube with just water + table sugar (1.020) and added a drop of Fermcap without seeing any change in the reading... but I'm not sure how good this test is if fermcap works to break surface tension better in the acidic wort??? I really don't know.

Any ideas and information are much appreciated.

Thank you!

 

[Just_Mike]

Just plugged your numbers into my software and I come up with 1.047
The rye alone only added 1.025.

 

[ajansen34]

Just plugged your numbers into my software and I come up with 1.047
The rye alone only added 1.025.

Must have wrong Rye liquid malt extract entered in your software. I just got my answer from another forum. My dumb ass took the hydro reading right after adding the top off water and got a diluted sample. Just took a reading again right as I'm just starting to see airlock activity and I'm right at 1.070.

Thank you for the response though

 

[AmandaK]

Fermcap S should have not influence gravity readings.

 

[cervezarara]

If this is the rye LME, NB says it adds 35 ppg. The DME should give 44ppg. Thus,

(6lb X 35) + (3 lb X 44) =
210 + 132 =
342 points /5 gallons=
68.4 points

Your OG should have been very close to 1.068. I have never observed that fermcap has had any effect on hydrometer readings. If you did a partial boil with top off, it is much more likely that your wort was not completely blended with the water, giving a false reading. With extract brewing, all the sugars are already present, and the only way you can miss the OG is if you left some extract out or if you topped off to the incorrect volume.

Hope this turns out well for you!