Gravity reading much lower than exected: why?

Okay, so my friend and me made an experiment yesterday. We wanted to brew a >20%, 300+ IBU IIPA.

Yeah yeah... I know :)

Now to the question. We used 10.5kg of grain for 26.25 liters of water for the mash. From the recipe calculator, we should have gotten around 1.208 OG. We "only" managed to get it to 1.120.

I wanted to ask if anyone had an idea of that poor efficiency. Mash went wonderfully at a temperature of 66°C.

  • Is there some point where converting to sugars in mash gets a lot harder?
  • Is the hydrometer capable of reading very high gravity readings?
  • Is there anything that you can think of that could create this result?

This is for a 3 gallons batch (11.5 liters).

Thanks!

Topic high-gravity mash beer homebrew efficiency

Category Mac

1
answered at

Your efficiency goes down as the gravity of your beer goes up. That's because of the sugar you leave behind when using a "normal" amount of water. In order to increase your effieincy, you need to sparge more. That also means you need to boil longer to drive off the extra water.

1
answered at

Putting 10.5kg of grain in 11.5 litres of water will kill your efficiency, unfortunately:

From Braukaiser:

Traditional British style infusion mashes are with about 2-2.5 l/kg (1 - 1.15 qt/lb) very thick and German style mashes are generally much thinner (3.5-5 l/kg / 1.75-2.5 qt/lb). Historically this is rooted in the fact that the latter needed to be pumped and stirred.

In the limit of attenuation experiments it was shown that a 5 l/kg (2.4 qt/lb) mash showed much better conversion efficiency than a 2.5 l/kg (1.2 qt/lb) mash. This is also supported by anecdotal experience from home brewers who found that thin mashes generally lead to better overall efficiency.

Comparatively, you had 1.095 l/kg mash thickness. If you want to try again, I would recommend you read the 21% Alcohol All-Grain Beer article on byo.com. The author gets around the issue you encountered by using far, far more water (better conversion efficiency), then boiling it down to a usable final volume.

Good luck!

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