Does more ferm sugars mean a higher FG?

[TripleC223]

I brewed a hefeweizen and used 2 more pounds of DME than the recipe called for (called for 5, I used 7). I used one packet of Mangrove Jack M20 Bavarian Wheat dried yeast, which has an attenuation of 70-76%.



Since the attenuation of the yeast is a constant, would that mean the more sugars that are available in the wort, the higher the final gravity will be?



I only ask because I'm two weeks past brew day and the gravity is still ~1.025. I was hoping to end at 1.014.



Also I know RDWHAHB and all -- just trying to learn something along the way. I won't do anything stupid.

 

[raysmithtx]

Are you checking the gravity with a hydrometer or a refractometer?

 

[TripleC223]

Are you checking the gravity with a hydrometer or a refractometer?

Hydrometer

 

[myntz]

What was your O.G.? For 5 gallons, 7lbs dme gets you to ~1.54 so that certainly looks as though it stalled out to me.

 

[Brownalemikie]

I'm not sure but it seems to me that you put in more fermentable sugars than the yeast can handle. Let's see what the experts say.

 

[Stillraining]

Need to know if there was any unfermentable's such as seeped grains. Those will have a impact on FG

 

[Calder]

Additional extract will raise the FG. 2 lbs of DME in 5 gallons will raise the FG by approx .005.

1.025 does seem high. I would recommend you provide more details about recipe and process, if you want someone to try and figure out what happened.

 

[TripleC223]

Here's what I went with:

1/2 lb flaked wheat (steeped 30 mins)
1/2 lb flaked oats (steeped 30 mins)
7 lbs Briess wheat DME
1 oz hallertau hops (full boil)
1 packet Mangrove Jack Bavarian Wheat M20 dry yeast

After steeping the grains, boiled DME and hops for 60 minutes. Pitched the dried yeast directly into the wort at 68 degrees.

I calculated my OG (BrewSmith) at 1.057. I took a reading with my hydrometer but it was way off, 1.070. I chalked that up to the wort not being mixed properly. I aerated as I have in my past batches, rocking the fermenter back and forth for 1-2 minutes.

It has been at room temp (60-66 deg) during fermentation.

Gravity at 10 days was 1.026.

Gravity at 14 days wasn't much different. Maybe 1.024 at best.

 

[Curtis2010]

1.025 is gonna be rather sweet. Hows it taste now?

What is the alcohol tolerance of the yeast?

 

[Curtis2010]

Just a side note: no need to boil DME.

Also fermentation generates heat. With an ambient temp of 60-66, wort could be getting close to 70 at peak ferm. Whats the temp range of the yeast?

 

[Curtis2010]

...


Since the attenuation of the yeast is a constant, would that mean the more sugars that are available in the wort, the higher the final gravity will be?

...

Only if the yeast can tolerate the additional alcohol (assuming no other factors affected the yeast).

 

[TripleC223]

I see the alcohol tolerance listed as 7.5% here. That sound right?

http://shop.greatfermentations.com/...arian-wheat-yeast/mangrove-jack-brewing-yeast

 

[jd1984]

No one has mentioned yet but your steeping grains probably needed to be mini-mashed. Flaked wheat and flaked oats do not have a lot of diastatic power. So, you likely have unconverted starch in there that won't be consumed by yeast.

 

[TripleC223]

No one has mentioned yet but your steeping grains probably needed to be mini-mashed. Flaked wheat and flaked oats do not have a lot of diastatic power. So, you likely have unconverted starch in there that won't be consumed by yeast.

That's actually something I learned before I brewed, but I went ahead with it because I still wanted to get the body and head retention out of the steeping grains.

That said, would those unconverted starches somehow prevent the yeast from fermenting some of the sugars from the DME?

 

[Calder]

The starches will not affect anything, except make the beer cloudy.

7 lbs DME in 5 gallons should yield 1.063.

I see no reason why you should be finishing at 1.025 (60% attenuation).

Sorry, I'd like to be able to give you some reason why you have a high FG, but I have nothing.

 

[TripleC223]

I will give it another week to see what happens. Anything else I should do in the meantime? Increasing the temperature will be difficult, as I don't have anything set up to manage that other than pointing a space heater at it in the closet.

If it doesn't change, can I (or should I, rather) pitch another yeast packet?

 

[Curtis2010]

I see the alcohol tolerance listed as 7.5% here. That sound right?

http://shop.greatfermentations.com/...arian-wheat-yeast/mangrove-jack-brewing-yeast

Now, just do the math and see what the ABV of your brew is.

 

[brandonlovesbeer]

Flaked grains are typically Unfermentable. So that may be where the extra gravity points are coming in. Without the additional DME you said the FG should have been 1.014. And since you added 2 additional pounds of DME it is now 1.025. So that looks about right.

 

[TripleC223]

Flaked grains are typically Unfermentable. So that may be where the extra gravity points are coming in. Without the additional DME you said the FG should have been 1.014. And since you added 2 additional pounds of DME it is now 1.025. So that looks about right.

So would that mean with the unfermentables, my OG was probably higher than 1.063? Based on that OG, the current ABV (at 1.025) would be ~5% with an attenuation of ~60%. That's lower than I had expected, but if my OG estimate was low, then those numbers would be higher...right?

FWIW, the gravity samples taste great. Not overly sweet. Also I noticed that between day 10 and 14, the smell changed drastically from cloves to a sweeter banana-like aroma. I'll still let this go for a few more days to see if the gravity changes.

As a takeaway, does that mean steeping certain grains will shift the range of OG and FG due to unfermentable starches? I.e., in this case, the 7 pounds of DME fermented appropriately, but my FG reading would still be "high" because of the remaining unfermentables? My numbers are just off because I miscalculated the OG?

 

[Stillraining]

As a takeaway, does that mean steeping certain grains will shift the range of OG and FG due to unfermentable starches?

Yes...Its the Unfermentable sugars and starches.. Anything with a >L20 rating is going to be pretty much unfermentable with out some serious effort and knowledge.

 

[TripleC223]

Its the Unfermentable sugars.. Anything with a >L20 rating is going to be pretty much unfermentable with out some serious effort and knowledge.

Got it. And I didn't expect to get any fermentable sugars from the steeping grains (flaked wheat and oats). I just wanted to get some more body and head retention from those and let the 7 pounds of DME provide the fermentables.

Is it possible that the DME has fermented properly, but the beer has finished with a higher gravity because of the unfermentable sugars produced by the steeping grains? Would steeping a half pound of flaked wheat and a half pound of flaked oats boost FG by that much?

 

[standpoint]

Are you sure you ended up with five gallons of wort? If you have less, that would account for the gravity difference.

 

[Stillraining]

Would steeping a half pound of flaked wheat and a half pound of flaked oats boost FG by that much?

About .005 so add that to an average dry finish ferment of say the 1.012 to 1.014 range and you get .017 to .019 .....your not off by all that much IMO...Drink it and move on.

Have you checked your hydrometer for reading 1.000 with just water?


Make beer and dont sweat the little stuff.
FWIW I rarely take FG's anymore, but I have a lot of brews under my belt and know my yeasts I use pretty well. All your really worried about in the beginning especially with DME is just not ending up with bottle bombs...I highly doubt this beer presents that problem..I would not hesitate one second in bottling it up if it were mine. Some ferments just go that way with nothing you did being necessarily wrong.
DME is also in itself a slight variable...they are not 100% all the same, nor give 100% repeatable results, batch to batch from the maulter's

 

[IslandLizard]

I'd say the problem lies in steeping those flaked grains:

1/2 lb flaked wheat (steeped 30 mins)
1/2 lb flaked oats (steeped 30 mins)​

They added a lot of extra starch to your wort, now beer, which can't be fermented (by regular beer yeast) and raises your final gravity. Wasn't the wort looking white and milky after the boil?

Next time you need to mash those flaked grains before the boil by adding 2 pounds of milled 2-row or wheat malt to them, and mash at 152°F for an hour. Then collect all the clear wort, leaving the damp grains behind. The starches will have been converted to sugars. You'll need to use less DME to get to your gravity.

See How to Brew: Section 3 - Brewing All-Grain Beer. In your case you would do a "partial mash," supplying the rest of the sugars with an DME addition to the boil kettle.

The beer you got now, bottle it and drink away. It may be much better than you think.

 

[TripleC223]

Make beer and dont sweat the little stuff.

Easier said than done! It's hard to know what's "little stuff" and what's more when you're only three brews in.

But seriously, your response was very helpful and confirmed a lot of my suspicions. I'm sure it's good enough to bottle, and the fact that it tastes and smells like decent beer (if not better) is encouraging. I will bottle this week and report back later.

You guys rock. :rockin:

 

[Calder]

About .005 so add that to an average dry finish ferment of say the 1.012 to 1.014 range and you get .017 to .019 .....your not off by all that much IMO...Drink it and move on.

I'd say the problem lies in steeping those flaked grains:

1/2 lb flaked wheat (steeped 30 mins)
1/2 lb flaked oats (steeped 30 mins)​

They added a lot of extra starch to your wort, now beer, which can't be fermented (by regular beer yeast) and raises your final gravity. Wasn't the wort looking white and milky after the boil?

Are you sure about this? I think the starch is in supension and makes the beer cloudy, but I don't believe it is dissolved in the wort, and therefore doesn't raise the gravity.

 

[brandonlovesbeer]

So would that mean with the unfermentables, my OG was probably higher than 1.063? Based on that OG, the current ABV (at 1.025) would be ~5% with an attenuation of ~60%. That's lower than I had expected, but if my OG estimate was low, then those numbers would be higher...right?

Did you not take an OG?
And for future reference the OG and FG on kits are only a guideline and not hard coded. Like Ian Malcolm's chaos theory states. Any factors can alter the outcome.

 

[TripleC223]

Did you not take an OG?
And for future reference the OG and FG on kits are only a guideline and not hard coded. Like Ian Malcolm's chaos theory states. Any factors can alter the outcome.

My OG was 1.070, but I have been off on that reading in my last two brews. Since I have only brewed extract, I believe those readings are affected by poorly mixed wort, despite my best efforts to counteract that.

I based the OG on the BeerSmith calculation, and another online brewing calculator gave me a similar output of 1.068.

However, somebody else on this thread recently asked about the volume of the batch. I actually checked and its only 4.5 gallons, opposed to the 5 it was supposed to be. I guess there was a lot of foam when I topped it off, and I shorted it a bit.

Would shorting a 5-gallon batch by a half gallon affect the FG that much? Wouldn't the unfermented sugars be more concentrated, therefore raising the FG? Would it account for that much of a difference?

 

[raysmithtx]

Would shorting a 5-gallon batch by a half gallon affect the FG that much? Wouldn't the unfermented sugars be more concentrated, therefore raising the FG? Would it account for that much of a difference?

Shorting the volume by .5 gallons or about 11% will increase your OG by the same amount, 11%.
So if the projected OG at 5 gallons was 1.068 then the new OG with 4.5 gallons ~1.075.

 

[TripleC223]

Shorting the volume by .5 gallons or about 11% will increase your FG by the same amount, 11%.
So if the projected FG at 5 gallons was 1.068 then the new FG with 4.5 gallons ~1.075.

That makes sense. I assume you meant OG for these figures. By those calculations, the lower volume of 4.5 gallons would yield an adjusted FG range of 1.020 to 1.024 (originally 1.014 to 1.018).

Would that, coupled with whatever unfermentables produced by the steeped flaked wheat and oats, explain the FG of ~1.026 that won't budge?