Beer Forum

If I calculated a grain bill so that I collect 6.5 gallons of 1.065 wort. The final runnings from my mash tun were 1.030 when all the water was drained, did I sparge too fast? And yes.. I ended up a bit short of my target O.G. even though my refractometer said my pre-boil gravity was right on (go figure that one). And yes again... I am pretty new to all grain and even newer to my system.

J.Brew wrote:If I calculated a grain bill so that I collect 6.5 gallons of 1.065 wort and the final runnings from my mash tun were 1.030 when all the water was drained, did I sparge too fast? And yes.. I ended up a bit short of my target O.G. even though my refractometer said my pre-boli gravity was right on, AND I ended up SHORT of my target volume( (go figure that one). And yes again... I am pretty new to all grain and even newer to my system.

There are so many variables to look at here it is hard to figure out where to start. Let's start with your refractometer. Have you checked it side by side with your hydrometer on the same wort to make sure they agree? If not, you should do that so you can get the right correction factor for your refractometer readings. You can set that correction factor in the systems settings menu on Promash.

The other place to look is how you arrived at your expected pre boil gravity. Lots of folks use the boil off calculator in software like Promash to figure what their preboil gravity should be based on their desired final gravity. If the rate of boiloff is incorrect, your projected gravity will be way off. When using that calculator, be sure to use volume/hour rather than %/hour for the boil off rate. The volume/hour rate will remain pretty much constant as long as you use the same pot. The %/hour will vary with the amount of wort in your pot.

After typing most of this about 3 times and completely dumping most of what I wrote, I'm not exactly sure where your problem is other than checking the above items. The way I read it was that you got the right preboil gravity and volume and that you got too low post boil gravity and volume. Since that can't happen (unless you had a short boil and spilled a bunch of wort) there has to be an error in measurement of either gravity or volume somewhere.

Assuming you fly sparged, the 1.030 figure shows you probably sparged too fast. Batch sparging would solve that problem.

Anyone else want to take a shot at this? I've been thinking too much on this. Need another beer.

Wayne
Bugeater Brewing Company

Yeah i know there are an ass load of variables here and if you put too much thought into it it you just might snap and end up in the fetal positon in the corner of your living room naked, chanting "Augustina Barruna" over and over and eating dog food. I agree with you that it is most certainly opperator error. My measurements are off somewhere and I haven't taken much time to determine the correction factor for my refractometer (my pre-boil WAS determined by a % factor on promash, so thanks for the heads-up). My real question was about the gravity of my final runnings. I am getting to know my system and would very m uch like to master fly sparging before I move to batch as I feel it would make me a better brewer. I wnat the experience. I will certainly spend some time with my refractometer and slow down my sparge...