Cedar Rapids Brewing Society

Here is the background to my question:
I just brewed a RIS with a total grain weight of 23.55 lbs. "Beersmith" estimated my OG at 1.125 if I had 75% efficiency. My measured OG was 1.084 for about 50%. This was not a surprise, in fact, the author of the recipe warned against lower efficiency and suggested 5-6 lbs more base malt to up the OG. I was pushing the limit of my 10gal mash tun with a 1qt/lb mash ratio as it was. Anyway, the recipe stated that the FG of 1.037 was important for balance(based on an OG of 1.100). Here is my question: Given my lower OG and wishing to have a balance close to the recipe, can I figure a FG 1.021(.016 lower than the recipe) and expect the same balance results? Or is there a more complicated algorithm?
Question #2: I mashed at 149 for 90 min. with a 1qt/lb ratio. I use a 10gal Igloo cooler for a mash tun. I got an efficiency of just 50%. Any suggestions on how to increase the efficiency of this system?
Thanks

John,
I can't help you with the tougher question, but you can always add some DME to get the OG back up there. Sorry if that's too obvious...

May be from the 1 qt/lbs. I use to do 1.25 qt/lbs. Now that I re-circulate with a pump I use 1.5 qts. I adjust my final volume, for example do 7.5 gallons instead of 10 so I can mash at normal ratios. For a gravity that big DME is a good solution. You can also collect more volume and boil longer to reduce to your gravity.

I would add DME to make up the OG. That said big thick mashes can be hard to convert. The enzymes have trouble moving freely through the tight grain as well as a tough sparge though the porridge (channelling). I would scale back to a smaller volume to easier fit the tun (as Matt said). You could also stir the mash and lightly rake the top of the grain bed a couple times during the sparge.

- As Matt said up you qt/lb ratio I would go as high as 1.5 (try spliting the mash up to two tuns if you don't have the room) THIS IS PROBABLY YOUR BIGGEST PROBLEM.
- Make sure that you stir very thoughly at the beginning.
- Stir a couple of times in the middle of the mash to reduce cool spots.
- Use a batch sparge and use the second sparge to do a second mash on it, then rinse with a smaller amount of water at higher temp to shut down conversion.

http://braukaiser.com/download/Troester ... ciency.pdf

The above link gives a great overview of how to control & predict efficiency. If you batch sparge, reference slides 18-20.

In addition to the slides presented at NHC, there is a lot of good info at the braukaiser.com site. The owner does a lot of controlled experiments and provides very detailed presentations of the results.

DrPaulsen wrote:http://braukaiser.com/download/Troester ... ciency.pdf

The above link gives a great overview of how to control & predict efficiency. If you batch sparge, reference slides 18-20.

In addition to the slides presented at NHC, there is a lot of good info at the braukaiser.com site. The owner does a lot of controlled experiments and provides very detailed presentations of the results.

Thanks, for posting, that is a great presentation on effenciency. All should read.