Low FG cause and effects

[FalconBrew]

First post here so bear with me. Little history, started homebrewing about one year ago and did 11 extract beers before upgrading to a basic all grain system. First two all grain beers came out perfect, hit SG & FG and they are great.

Fast forward to batch three, an american wheat beer all grain. This was the first kit in which the grains did not come milled. I got busy with Summer things and the kit sat in the basement cool and dry for about 2 months before brew day. I do not own a grain mill so we tried crushing the grains with a rolling pin. Used a fair amount of force and tried rolling them until all husks were cracked but not pulverized. Mashed for 60 min @ roughly 151 degrees.

This is where things started to turn for the worst. Did my initial vorlauf runnings and began the batch sparge. Wort came out nice at first but sparge water seemed to run through very quickly. After only about 20 min of sparging the wort began to run awfully clear. I finished sparging to bring boil volume to roughly 6.5 gallons. After this things went pretty normal but after cooling, when I went to transfer to primary, I came up about 1 gallon short and had to top off with water. I am not sure why I came up so short on wort this time as the others came out to nearly 5 gallons each time. Was short on time and in a hurry , so I forgot to take a SG reading and just aerated and put into storage for fermentation.

Fermentation began as usual overnight and a thin krausen (1/2-3/4") had formed and things seemed normal. Fast forward to about 36 hours and the krausen line was no higher and was actually beginning to fall and airlock activity was slow. After 48 hours fermentation appeared to be at a halt. After 72 hours I drew a sample and did a hydrometer reading at it read 1.002 and FG of the beer was supposed to be 1.010-1.020 ideally. I did smell and taste the sample and it seemed perfectly fine, no odd smells or off tastes that I can perceive.

I am admittedly not really good at understanding the science behind yet. Can someone please help explain what I may have done wrong and if it will affect the final product?

 

[SunsetBrewery]

First problem is crushing your grains with a rolling pin. This will cause an OG/SG to be off. Secondly, Don’t top off with water if you don’t know your OG. Only top off with water if your OG is high & you want to lower it. I used to come up short until I learned my System. Do you use Brewing program like Beer Smith or any other free ones out there? They will help with water mashing water & sparge water amounts. It’s also okay that your wort started running clear during sparging. That’s a good thing. You obviously batch sparge....right? If you fly sparge....20mins isn’t long enough. What I used to do when I was batch sparging is I’d split the sparge water in half & do 2 separate batch sparges. I’d also run them real slow (about 30mins each)

 

[FalconBrew]

Yes, batch sparge. The thin krausen, fast fermentation, and low fg concern me the most. Are they all a bi-product of what was likely a low SG? Should I still expect this beer to turn out ok, maybe just a little low in abv?

 

[RPh_Guy]

+1 Rolling pin is likely the culprit.
Your OG had to be very low, like 1.008.... 0.75% ABV.

Buy milled grain or buy a mill

 

[SunsetBrewery]

Wheat beers will usually ferment out fast. I will let my wheat beer go in the primary for at least a week (I notice no bubbling after like 3-4 days. Thought it was stuck the 1st time I brew a wheat beer) & transfer to secondary for another week. My guess is (that since you were in a hurry & forgot to take an OG) that your OG was low since you tried crushing your grains with a rolling pin. I wouldn’t worry about it. Some beers have a vigorous fermentation & others don’t. Last wheat beer I did I was fermenting in a bucket. So I can’t see the Krausen. But I do use a blowoff tube & never had any come through that with a wheat beer like other beers. You smelled & tasted & it was fine. You should be alright. Just maybe a thinner beer than what you expected

 

[bleme]

My guess is that your grains weren't as cracked as you think and you ended up with Near-Beer. You will probably have to drink a gallon of it to know for sure though.

 

[FalconBrew]

Is it possible to add DME or something to the primary to restart fermentation and boost abv?

 

[SunsetBrewery]

Don’t add any DME after fermentation. You can add another package/vial of yeast if you want to try & restart fermentation if you want too. I just know my wheat beer usually ferments out in 3-4 days. If you had taken a OG before adding yeast....you could’ve added some Light DME until you reached your targeted OG

 

[RPh_Guy]

I'd chalk it up as a learning experience and try it again (with actually milled grain).

You can add another package/vial of yeast if you want too.

Lol. What?

 

[FalconBrew]

Thanks for the info. Live and learn I guess.

 

[SunsetBrewery]

I'd chalk it up as a learning experience and try it again (with actually milled grain).


Lol. What?

Yeah. If he wanted to restart fermentation....I’d rack wort to a new fermenter & pitching a fresh batch of yeast. I wouldn’t since his gravity is already low at 1.002.

 

[RPh_Guy]

What a weird thread. I have some food for thought.

S.G. = Specific Gravity. Measure of density.
O.G. = Original Gravity. The SG before fermentation.
F.G. = Final Gravity. The SG after fermentation.

In an average wort, an average yeast will attenuate around 75%. Therefore an FG of 1.002 likely had an OG of 1.008 (+/- 2 points). A calculator shows ABV of 0.8%.

...So what he has there is basically a hop tea with just enough extras to cause problems. He could add DME but would need to degas it to prevent foaming and heat it to dissolve the DME. This could cause oxidation flavors, extract more hop bitterness, kill the yeast, and remove the alcohol. May as well just start over with water.
I don't think knowing the OG would change any of that.

There's nothing wrong with adding water post-boil if you're trying to target a particular OG or volume. Also totally fine if you don't. It's all good.

There's no reason a wheat beer would ferment any faster than a beer with less wheat. It's much more dependent on the yeast health/quantity, temperature, nutrients, OG, and wort fermentability. Most moderate OG homebrew beers will ferment in 3-7 days with good yeast health.

After fermentation finishes, there are no more fermentable sugars. Adding more yeast after fermentation will not cause further attenuation. (Normally)

Currently the use of a "secondary" vessel is widely regarded as unnecessary, and potentially harmful (via contamination and oxidation). It does not help with clarity.

Happy brewing!