In retrospect, this was a lot to change at once. I went from extract to all-grain. I swapped out my kettle, immersion chiller, and other equipment for The Grainfather, all-grain brewing, and all-new recipes. I did this without any help or guidance from others, apart from my own reading. It's kind of surprising that I haven't had to toss a single Grainfather-made batch.
A recurring problem for me was that my final post-boil volume and gravity were rarely close to my recipes. If my recipe was supposed to yield 5 gallons at 1.045 gravity, I'd end up with 5.5 gallons at 1.038 or 1.040. Even when I boiled down to the target volume, my gravity was usually low.
Finally, I found that the problems were:
- I'd been using the default sparge water calculation in the manual. This meant that I was calculating sparge water based on a six-gallon batch instead of five gallons. Adjusting the calculation for a five-gallon batch got me closer to the final volume target.
- I didn't know enough about enzymes and their role in mashing. In Palmer's book, I learned that the optimum balance of mash water to grain for a 60-minute mash is 1.5 quarts of water per pound of grain in the mash. The Grainfather's figure results in a thinner mash that needs more time to convert starch to sugar.
The gravity problem was solved using three techniques as needed:
- The adjusted sparge water calculation reduced pre-boil volume by one gallon.
- In a few cases, my volumes were still a little high near the end of the boil. In these cases, I removed the hops bags (to prevent over-bittering) and continued boiling until I hit the target.
- Adding malt extract near the end of the boil to increase the gravity is also an option.
That last item (adding extract) carries a couple of caveats. You should probably do this with at least 15 minutes left in the boil to ensure that the extract is boiled enough to sanitize it. A second caveat is that if you're adding liquid malt extract, I've found that this tends to fall to the bottom of the Grainfather kettle and trigger its thermal cut-out switch. This circuit-breaker-like device has to be reset by reaching underneath the Grainfather and pressing it in. That can be risky with a full kettle of wort. You're much better off using dry malt extract, which tends to float on the surface of the wort until it dissolves.
For my most-recent brew, a Blonde Ale, reducing the sparge water amount by a gallon allowed me to hit the post-boil volume on the mark. Extending the mash time from 60 minutes to 90 minutes seemed to solve the gravity issue for that batch, which had a slightly higher pre-boil gravity and an on-target final gravity. I have yet to have had to use malt extract since making those adjustments, but I keep some on-hand for just that contingency.
Other Grainfather posts on this site:
- The Grainfather - Initial Impressions
- The Grainfather - Test Run
- Grainfather All-Grain RIMS System - Walkthrough and Review
- Brewing with The Grainfather, Part 1 - Mashing and Sparging
- Brewing with The Grainfather, Part 2 - The Boil
- Brewing with The Grainfather, Part 3 - Cleaning and Overall Thoughts
- iMake's Graincoat Jacket for The Grainfather