Overshooting FG. What do you make of it?

[Vendrixfly]

Hey all. Need some help!

Brewed up two batches of a summer ale for my wedding and seem to have overshot the FG by a LOT and don't know why. Just kegged and took a reading on the second batch tonight and it ended the same as the first, with a FG of 1.002...Way below the 1.011 that iBrewmaster calculated. The two are practically the same recipe except that I was playing around with how much honey malt to use, so I'll give you the recipe that had the most fermentables in it:

5lbs 2-row
2lbs white wheat malt
.5lbs honey malt
1lb honey

.5oz Galena 60
1oz Fuggles 15
.5oz Fuggles 5

Aerated well and pitched Safale US-05 on the first and Wyeast 1056 on the second, and both underwent a 3 week primary and finished at 1.002. The hydrometer samples tasted fine, very light, but nice and healthy. Does this look okay? OG of first brew was 1.044, second 1.050.

Thanks for any help you might have.

 

[kingwood-kid]

1. Test your hydrometer in distilled water. Ideally at 60F, but whatever temp your beer was will work.
2. You probably mashed at a low temp, like 145F.
3. If you didn't raise the temp to 175ish before sparging, the enzymes kept working to make your beer more fermentable.
4. Honey (bees, not barley) or any other simple sugar will lower your FG, since alcohol is less dense than water.
5. Did you measure your OG at pitching temp or right off the boil? The temperature corrections are pretty unreliable at high temps.

 

[Vendrixfly]

The hydrometer readings were both taken at ~68 degrees after chilling and before kegging. Mash temps were between 150-153 using a thermometer that I've used before that measures boiling water at 212, and I BIAB so I mashed out both batches at 170 degrees for 10 minutes after the hour long mash, no sparge. I know honey can ferment to dry as I'm familiar with making meads and melomels of various types, but I just can't see how it got this low... Is it possible a wild yeast of some sort got into the brew? Like I said, I did not taste anything off in the samples, but I'm not the most experienced with things like that either. It tasted clean as can be.

Truth is, I've been having the same problem with all of my beers lately, all grain, partial mash, and extract. I hit the OG perfectly and the FG is always lower than it should be. Never by this much though.

 

[kingwood-kid]

Your recipe as written is pretty fermentable, with or without the honey. Brewing software doesn't really adjust for this; it just assigns an attenuation level to each yeast. My beers always end up lower than projected. If I increase the attenuation by about 5%, I get a better estimate. Probably something to do with my never using crystal malts.

You can mash at 155. You can shorten your mash times to 40 min or so. Pretty much all the starch will convert in 20-30 min, especially with recipes high in American 2-row. After that point, you're just trading dextrins for fermentables. Maybe add some carapils for insurance.

 

[Vendrixfly]

Thanks again for the feedback! All great suggestions. Interesting about the software calculations...figured something may not have been accounted for in projected FG.

Gotta kick the two kegs in the kegerator now and pop these batches in to carbonate. Hopefully I won't end up with cold carbonated beer water! Ya live, ya learn.

 

[dukes7779]

I have had similar experiences with overshot OGs and lower FGs. The way I see it, it is what it is, and the next time I brew it I will know what to expect. I don't really worry about differences in iBrewmaster calculations because in the batch view you will enter actual gravities and that is what I base my next batches on. Although I have asked many questions here along the way to gain knowledge and get valuable input from experienced brewers I always end up maintaining Charlie Papazians RDWHAHB philosophy as long as my final product is (drinkable) beer!!

 

[Vendrixfly]

Totally! I usually don't fuss too much about it, but as this beer is for my wedding I got a bit concerned. No worries though, there's still time to brew up a couple more batches before June if these are lacking. Gonna drink em anyway!