How to lower Final Gravity?

Question

I made a Thomas Coopers Stout with 1.1kg of dark malt extract and 400g of maltodextrin and used the yeast that came with it. I got a Starting Gravity of 1.046 and Final Gravity of 1.024.

Are there any tips to get the Final Gravity lower in order to get a higher alcohol content?

Answer 1

Almost one third of your gravity is coming from maltodextrin powder. This stuff is non fermentable and should be used at a lower percentage. Also whatever yeast came with the kit is possibly old and unreliable.

You probably won't get this batch to go any lower but you can make a couple changes and brew it again.

1. Use only 5-10% of the total gravity points with the maltodextrin next time. It will still provide body and not artificially hold up the FG.
2. Be sure of the freshness of your yeast source. Or at the very least use two packets.
3. While using dry yeast give them a better chance and rehydrate them in water first. Boil and cool a cup to a pint of water so its sanitary, then sprinkle the dried yeast packets in there 20 minutes prior to pitching into the wort. Rehydrating improves the viability of the yeast by close to 50% when compared to putting it directly in wort to rehydrate.
4. After 5 days of fermentation try and warm the beer up to 70-72F. This tends to give the yeast a little encouragement as the nutrients are beginning to wane and the yeast are getting tired.

Good luck

Answer 2

You may not be able to get it lower without using enzymes. Maltodextrin is non fermentable, and most dark malts have a large amount of non-fermentables from the kilning process.

Adding some dry beer enzyme or beano will break down the complex sugars in the dark malt, and some of other nonfermentables, but you may end up with a thin beer afterwards.

A more controllable approach is to blend the beer with a low gravity, higher alcohol beer, but this of course requires another batch of beer.

Answer 3

If you think fermentation is incomplete you could try pitching a healthy starter of a different ale yeast obtained from a known good source.

As other have said however it's likely that most of those residual gravity points are coming from unfermentables like maltodextrin. In that case you are not likely to ever get a substantially lower FG. If you only want more alcohol you can add table sugar and wait for it to ferment out. Just be aware that it will affect the flavor profile of your finished beer, making it taste 'hotter' or cider-like.

Answer 4

How did you measure your final gravity? I use a Refractometer and FG readings need to be adjusted for alcohol. I use http://onebeer.net/refractometer.shtml to calculate ABV and http://www.brewheads.com/brixsg.php to convert from SG/FG to Brix/Plato