High FG in Mini-Mash

[milo_leon]

Hello all,

I am brewing a Double Chocolate Stout. This was my first mini-mash so I followed DeathBrewer's "Easy Partial Mash Brewing" guide which was a big help!

It was a mini-mash recipe with about 3.75 lbs of grain mashed at ~155 degrees for 45 minutes then I teabagged the grain in a second pot containing 170 degree sparge water for ten mins then poured the wort back in my brew kettle. I added 5 lbs of dark extract and 8 oz of malto dextrin. During the boil, I added 1 oz galena (bittering hops) at 60 min, irish moss/yeast fuel at 15 min, and 1 oz cocoa powder at 5 min. After cooling the wort down, I pitched White Labs London Ale WLP013.

I left it in primary for two weeks, and recently transferred to secondary where I added 2 vanilla beans soaked in 1/2 cup of Makers Mark (I also added the bourbon to the secondary), 3.75 lbs of raspberries, and 1 oz of unsweetened cocoa powder. I plan to let this epic concoction sit for 2-3 weeks.

My OG was 1.062 (should be 1.056) and my FG was 1.030 (should be 1.012). I am wondering what could cause my FG to be so high? I have several theories-

• I pitched too warm. I ran out of cold water at my apartment thus the wort chiller wasn't working as well. I pitched around 80 degrees. I usually aim for 65-75 and let the yeast warm up in the wort.
• I don't have a system to manage my fermentation temperature (yet), so it was probably fermenting around 70-75 degrees in my closet. Would this stall out the fermentation process?
• Was two weeks not long enough in the primary? My recipe said to transfer after 5-7 days which IMO is a ridiculously short timeframe.

Any other ideas on why my FG may be high?

My beer is actually re-fermenting in the carboy, probably due to the sugars from the raspberries. Will this help bring down my FG?


I am actually hoping for a sweeter beer that will play well with the raspberry/vanilla since I read the unsweetened cocoa powder can make a bitter beer, so maybe the high FG is a blessing in disguise.

 

[IL1kebeer]

Did you take your FG reading before or after you added the raspberries?

And are you sure that your beer was done fermenting when you took your FG reading? Was the reading stable for 3 days? With a healthy ferment, more beers will be done before two weeks; however we can assume that your fermentation might not have been healthy enough to finish in two weeks since you didn't use a starter and your OG was above 1.060. Also, how old was the yeast that you used. If it was over two months out of the lab then it probably took at least 4 days to even get started.

 

[milo_leon]

Did you take your FG reading before or after you added the raspberries?

And are you sure that your beer was done fermenting when you took your FG reading? Was the reading stable for 3 days? With a healthy ferment, more beers will be done before two weeks, but since your OG was above 1.060 and you didn't say that you used a starter then we can assume that your fermentation might not have been healthy enough to finish in two weeks.

Yeah I measured the FG in the primary before I transferred to secondary. I did not use a starter, it was liquid yeast in a tube.

 

[IL1kebeer]

Yeah I measured the FG in the primary before I transferred to secondary. I did not use a starter, it was liquid yeast in a tube.

Do you still have the vial? How old was it? Before I started using starters I pitched a 3 month old vial into a 1.068 OG IPA. That beer took 4 days to start fermenting and then another 15 days to get to FG. It was drinkable but I wasn't proud of it. The last batch I did I used the appropriate sized starter and the beer hit FG in 5 days. I gave it a few more days to clean up and kegged at 8 days.

Your beer may have very well still been fermenting... Which is good news because your FG will continue to drop. The bad news is that you under pitched, even if your. OG was the expected 1.056 you still under pitched. I'm not going to sit here and tell you that your beer is going to come out bad because it's probably ok, but you should go research the benefits of using a starter and the negative effects of under pitching.

 

[milo_leon]

Do you still have the vial? How old was it? Before I started using starters I pitched a 3 month old vial into a 1.068 OG IPA. That beer took 4 days to start fermenting and then another 15 days to get to FG. It was drinkable but I wasn't proud of it.

Your beer may have very well still been fermenting... Which is good news because your FG will continue to drop. The bad news is that you under pitched. I'm not going to sit here and tell you that your beer is going to come out bad because it's probably ok, but you should go research the benefits of using a starter and the negative effects of under pitching.

I brewed the beer like 3 or 4 days after I got the kit from AHS. My beer took abt 36 hours to ferment and the bubbles lasted around 4 days. I know the bubbles are not a reliable sign of fermentation, but I figured 8-10 days after the bubbles stopped would give the yeast sufficient time to finish up.

I do have a yeast starter kit, but never used it. Maybe it's time I do

 

[IL1kebeer]

I brewed the beer like 3 or 4 days after I got the kit from AHS

Next time you buy a kit check the best by date on the whit labs vial. Subtract 4 months from that date and you will be within a week of the date that it was created. That will give you an idea of how good your retailer is at keeping fresh yeast. One LHBS near me regularly has vials that are three months old (less than 25% viability which is horrible). Another LHBS near me has only 1-2 month old yeast (50%-75%) viability. There is a huge difference between the quality yeast supplied by those stores. And it will madpke a huge difference with your brews, especially if you don't use a starter.

 

[Yooper]

Dark malt extract has less fermentable sugars in it (from darker crystal malt) and the recipe itself may have had some crystal malt and things that would make a higher FG.

 

[milo_leon]

Bump to update this- I took the FG after secondary fermentation. It was around 1.020-1.022. I measured after I poured in the priming sugar (forgot until last minute), how much would that affect my FG?

 

[IL1kebeer]

Bump to update this- I took the FG after secondary fermentation. It was around 1.020-1.022. I measured after I poured in the priming sugar (forgot until last minute), how much would that affect my FG?

Depends on the volume of sugar water that you added and the volume of beer that you added it to. Sugar adds 45 ppg. That means that 1 pound of sugar added to one gallon will give you 1.045 SG.

For example. If you dissolved 4oz of sugar in liquid that brought your fermenter volume to 5 gallons then it would add 2.25 gravity points:

45ppg * (4oz/16oz) = 11.25 points
11.25 points / 5 gallons = 2.25 points

You can input your values for weight of sugar and final fermenter volume in the equations above to get your answer.

*Edited - Added equations*

 

[milo_leon]

Depends on the volume of sugar water that you added and the volume of beer that you added it to. Sugar adds 45 ppg. That means that 1 pound of sugar added to one gallon will give you 1.045 SG. For example. If you dissolved 4oz of sugar in liquid that brought your fermenter volume to 5 gallons then it would add 2.25 gravity points: 45ppg / 4oz = 11.25 points per gallon 11.25 / 5 gallons = 2.25 points You can input your values for weight of sugar and final fermenter volume in the equations above to get your answer. *Edited - Added equations*

I added 3.5-4 oz sugar dissolved in 2 cups water. Volume was ~4.2 gal so am guessing FG went up 3-3.5 points?

 

[IL1kebeer]

I added 3.5-4 oz sugar dissolved in 2 cups water. Volume was ~4.2 gal so am guessing FG went up 3-3.5 points?

I edited and changed the first line of the equation a little.

With your numbers I got 2.35-2.68 points.