ABV issue

[Chcarpenter]

So I brewed my third batch on my new system am running into a brick wall with my ABV. It is not that it is low, but always high. My last beer I was understanding of because it was a kolsch and I played with the temp in my ferment chamber when I shouldn't have. I have a Belgian Dubbel in my ferment chamber at the moment and I just did a gravity reading yesterday which was 1.006. I started at 1.069, so I now have a 8.3% Dubbel. I use BeerSmith and planned my recipe out for it to be 7.3%. I am just not sure why I am so far over on my alcohol. It does not take hot at all which is good, but I'm just wanting to understand where my issue. Thoughts? Questions for me that you would like to ask?

 

[CGish]

If you could provide your recipe, mash temp, fermentation temp, and yeast used it might help.

 

[bobeer]

Basically, If you're brewing all grain and you mash too low you'll create more fermentable wort. Combine that with high attenuating yeast and you'll get a thinner, higher abv, beer. If you mash a little higher and use the appropriate yeast for the style of beer you're brewing you should get better results.

The mash usually depends on the style of beer you're brewing. Dry, west coast IPA's, are usually mashed lower and maltier beers are usually mashed a bit higher. Of course there are exceptions to these rules depending on what you're brewing and the yeast you're using...

Without knowing anything about the fine print of your recipe it's hard to determine the exact thing that's causing your issue.

 

[GrogNerd]

also, even if your mash temp is spot on or you take it higher, without a mash out, if your sparge water is not hot enough or you're not starting to boil your first runnings while collecting your sparge you can produce a more fermentable wort

gotta get that wort up to high enough temp to denature those enzymes, fix your fermentability where you want it

 

[Chcarpenter]

I am on a 20 gallon system and due to boil off and fermentation we aim of 25 gallons of wort in the boil kettle, which leaves us about between 22-23 gallons in the fermenter. Not sure what my begging amount will be for this recipe, but passed batches have about 18 gallons.

Amt Name Type # %/IBU
46.00 g Gypsum (Calcium Sulfate) (Mash 60.0 mins) Water Agent 1 -
27 lbs Pale Malt (2 Row) US (2.0 SRM) Grain 2 50.0 %
19 lbs Pilsner (2 Row) Ger (2.0 SRM) Grain 3 35.2 %
4 lbs Caramunich Malt (56.0 SRM) Grain 4 7.4 %
2 lbs Special B Malt (180.0 SRM) Grain 5 3.7 %
2 lbs Candi Syrup, D-90 (90.0 SRM) Extract 6 3.7 %
3.00 oz Tettnang [4.50 %] - Boil 90.0 min Hop 7 9.9 IBUs
3.00 oz Tettnang [4.50 %] - Boil 60.0 min Hop 8 9.3 IBUs
4.60 Items Whirlfloc Tablet (Boil 15.0 mins) Fining 9 -
2.00 oz Saaz [4.00 %] - Boil 10.0 min Hop 10 2.0 IBUs
3.0 pkg Belgian Ardennes (Wyeast Labs #3522) [124.21 ml] Yeast 11 -

We ran into a slight issue in our mash on this one (someone forgot to put the false bottom in the mash tun). The plan was to mash at 149 for 90 minutes and the fly sparge at 168. Due to the hiccup with the mash tun it was more like mashing at 130 for 30 minutes, and then 149 for 90 and still sparking at 168 (in the moment it was all we could think to do).

I did do a yeast starter, but not on a stir plate. I started it about 18 hour before hand (forgot about it). Fermentation went from 64 to 70 degrees over the course of 7 days, approximately 1 degree per day.

I can understand if my mash screwed up the abv on this one, but it just seems like I keep running into this issue and I'm just not sure why. Most likely it is something different overtime.

 

[eastoak]

with a large grain bill and a new system you will run into problems that will be solved mostly by time and practice, especially if you are a new brewer.

 

[GrogNerd]

Practice. Practice making beer

I just love saying that

 

[doug293cz]

...
We ran into a slight issue in our mash on this one (someone forgot to put the false bottom in the mash tun). The plan was to mash at 149 for 90 minutes and the fly sparge at 168. Due to the hiccup with the mash tun it was more like mashing at 130 for 30 minutes, and then 149 for 90 and still sparking at 168 (in the moment it was all we could think to do).
...

A 90 minute mash at 149°F will create a very fermentable wort. It's no surprise that you are getting such low FG's. To get higher FG's you should experiment with mash temps in the 152° - 156°F range.

Brew on

 

[Chcarpenter]

I did the 90 at 149 because of the Pilsner malt and the possibility of DMS. That may be my issue on these last 2 recipes

 

[GrogNerd]

Pilsner needs a 90-minute BOIL to drive off DMS precursors

 

[SnakeRidge]

Practice. Practice making beer

I just love saying that

You also got to practice drinking beer. Don't want to be like that chicken legged guy who can bench 500#.

 

[MrHopScotch]

I tend to have a similar issue and end up getting much better attenuation than beersmith estimates. I'll often try inputting different FG values that are more similar to my past experiences to get and idea of my ABV. If you find that for a particular yeast strain you are getting different than default attenuation, you should be able to change that value in the ingredient profile for the strain IIRC.

 

[Chcarpenter]

I had been doing 90 minute for the Pilsner malt because in Brewing Classic Styles Jamil says that you may need to do the 90 rest and 90 boil. Thus why I did that, I will look at shorting the rest time in the future with Pilsner malt.

 

[Billy-Klubb]

You also got to practice drinking beer. Don't want to be like that chicken legged guy who can bench 500#.

I cannot bench 500 lbs! 485 max.

sounds like low mash for a long time is your culprit. I had low mash problems at first until I started preheating my cooler/tun. I don't always hit my numbers, but that's not what brewing is to me (specifically).

 

[madscientist451]

If your goal is to have lower alcohol you could reduce your grain bill and use the same process or keep the grain bill the same and increase mash temp in the 152-156 range, as someone already suggested or keep your fermentation temperature down so the yeast doesn't attenuate as much. Adjusting your mash temp, malt bill and fermentation temperatures will have an effect on the flavors put off by the yeast. Are you getting a yeast character you are happy with now? If you wanted to change that, what would your target flavors be?
With a clean fermenting yeast like Cali ale, making adjustments for ABV can be a lot simpler compared to using a Belgian yeast which imparts a different flavor profile with changes in different variables.
I think for now maybe scale back to 5 gallon batches and tweak the mash temp and fermentation temp until you get the flavor/ABV you are looking for,
then scale it up and run your 20 gallon batches.

 

[Chcarpenter]

Thanks for the advise and thoughts. I have some thinking to do, and this has helped.

 

[GrogNerd]

I did the 90 at 149 because of the Pilsner malt and the possibility of DMS. That may be my issue on these last 2 recipes

I had been doing 90 minute for the Pilsner malt because in Brewing Classic Styles Jamil says that you may need to do the 90 rest and 90 boil. Thus why I did that, I will look at shorting the rest time in the future with Pilsner malt.

Jamil's Dubbel recipe is 68% Pilsner, while yours is 65% NOT Pilsner; you may not need the extra 30 minute mash

he also says, "you MAY NEED" the longer mash with Pilsner if the temp is below 150° to get full conversion.

maybe check for conversion at 60 minutes, let it go to 90 if it needs it.

but I think in your one instance, the ½ hour at 130 might have been the culprit