Higher FG on Vintage Beer

[monkeeroot]

I have been mulling through "The Homebrewer's Guide to Vintage Beer" and decided to give one of the recipes a go. I picked the "March 10th 1910, Fullers X" recipe but I'm having a problem figuring out how to get the FG of 1.015. When I plug everything into Beersmith, it shows my FG as being approximately 1.004. Even if I increase the mash temp from 149°F to 157°F it only brings me up to 1.007.

Is there some technique that I'm missing to get the higher FG?

The recipe is:

 

[NTexBrewer]

I don't use Beersmith but there should be somewhere that you can put in a custom Attenuation and set it for 71%

Are you using the recommended yeast?

Looking at wyeast's website Wyeast 1968 has an attenuation of 67 to 71% and White Lab 002 has an attenuation of 63 to 70%.

If you have a different yeast selected that may also be the problem.

 

[CraptainWirtz]

I think the recipe is just wrong. Isn't invert sugar 100% fermentable? Your recipe as posted seems to make the assumption that it's only ~71% fermentable. I assume Beersmith is calculating attenuation properly.

 

[monkeeroot]

Yes, I am using WLP002 yeast and the attenuation is set properly in Beersmith. I did a little looking about the invert sugar and the majority of the results stated that it is 95%-100% fermentable.

 

[strambo]

Yeah, I don't see 1.015 as being realistic with that grain bill and all that sugar.


Sent from my iPhone using Home Brew

 

[monkeeroot]

I think that I might try a thick mash at a higher temperature and see what happens. I'm going with 1qt/lb for the mash thickness and 160°F for temp. I'll start doing iodine checks at ~20 minutes and sparge when conversion is complete.

Beersmith still shows it finishing low with this mash profile but I'm not convinced that it is correct.