Islandboy85
Well-Known Member
How do you go about calculating your water volume you need for sparging? I've had some shortcomings the last few brews, and had to run indoors and heat up a gallon extra. Is there a general rule or some calculation?
total water=(desired post boil volume/0.96)/(0.925)+(lbs grain in mash x 0.2)+loss due to equipment. Roughly
I also forgot to add that I am slightly confused by the terminology "drain the mash tun" when people say they drain the mash tun before the sparge. Are you fully draining the wort out, or just draining until there is 1-2 inches of liquid above the gran bed? The same question for the sparge. Do you fully empty the tun or just drain until the liquid level is at the grain bed?
I completely drain the mlt before I add my sparge water. Then after adding sparge water I completely drain the mlt.
You have to differentiate between batch and fly sparging. With batch, you drain the tun. With fly, you don't.
V
So, if I wanted to get 6.25 gal preboil and had 10# of grist it would be 8.52 gallons total. If I'm using 1.5 qt/# I'd have 3.75 gallons strike water leaving me with 4.77 gallons to sparge. Is that right?
What is the significance of the 0.96 and 0.925 and 0.2 in the formula?
I may need to get beersmith... I wasn't sure. How far to collect down, so I stopped collecting at 1.010. I just got my refractometer. LOVE that thing.The .2 accounts for grain absorption in the mash tun. The .96 is for loss of volume due to the cooling of the wort and at the moment i forget the reason for dividing by .925, I have it written down at home. I see that your question is about sparge calculations. Beersmith has a good tool for that.
when fly sparging I heat a little more than my total pre boil target and sparge until i have collected my target volume. Never have ran out of water that way and the unused water is great for cleaning duty. I use a refractometer to check my SG as I go. Try not to sparge below 1.002 as you may start to extract tannins.
I think the concept seems weird to people who are converting over from batch sparging because we're used to completely draining the tun and then only having to discard damp spent grain. If you maintain a fluid bed to the very end, you actually end up with quite a bit of low gravity wort to throw away. I don't think it's detrimental to prepare a gallon or two less sparge water though because you only expose the top portion of the grain bed right at the end.
While we're on the topic of water volumes, can anyone explain how to calculate water volumes for a two step infusion mash? I'm brewing tomorrow, and this will be the first time I've attempted a protein rest. Beer Smith has some default values, but when I input my grain bill I get errors for the saccarification step because my infusion temp is above boiling.
I'm doing a dogfish 90 minute clone, looking at about an 18.1 lb grain bill. How can I figure out how much water I'm adding at each step?
The gravity was supposed to be 1.074 preboil?Grrrrrrrrr!!! What went wrong? I did AHS's Arrogant Bastard Ale clone. 13.5 # 2-Row, 1.5# Crystal 120. I mashed with 1.5 qt/#. I fly sparged with 5 gallons water. I wound up sparging until 1.015 and had a total of 6.75 gallons preboil gravity was 1.050. It was supposed to be 1.074 per the recipe. What did I do wrong? By the way, I have a 15 inch false bottom, so I should be getting way better results.
The gravity was supposed to be 1.074 preboil?
In any case, just based on my system you used a lot of water just to get 6.75 gal preboil. For example, I just brewed a batch that had 14 lb grain and used 38 qt total water, I had about 7.4 gal preboil.
But without details on exactly what you did it's hard to say. You said you stopped sparging at 1.015, did you leave a bunch of wort in the mash tun?
You said you mashed at 1.5 qt/lb so @ 15 lb grain that's 22.5 qt...then you said you sparged with 5 gal (20 qt) so that adds up to 42.5 qt total water.I used a total of 10 gallons water. I stopped at 1.015 because I was afraid of leaching tannins. AHS said to only collect 6.25 gallons for the same reason. 1.074 actually is the OG, sorry; but, for some reason this time I only gained 10 points on my boil. The boil and hop schedule was a 60 min boil, so I kind of had to stick with that to keep the hop schedule. I only had about a gallon and a half in my tun when I was done. An online calculator said I got 61 percent efficiency...that SUCKS.
You said you mashed at 1.5 qt/lb so @ 15 lb grain that's 22.5 qt...then you said you sparged with 5 gal (20 qt) so that adds up to 42.5 qt total water.
In any case, you can always boil longer if needed, you just need to calculate how much longer you need to boil and then add your bittering hops at 60 minutes remaining. Getting your volume and efficiency right will take some tweeking and you can accelerate the learning curve by taking careful measurements (and correct for temperature, water expands as it heats) throughout a brew day. Learning exactly how fast you boil-off and exactly how much 'unretrievable' wort you leave in the mash tun are two things I'd try to nail down first.
This last brew I had enough water, just not good extract efficiency and a crappy boil. I guess I'll just have to wait to see what it tastes like. It should be done soon since I used a yeast cake from a batch that just went into the secondary fermenter. I had to put a blowoff tube into the bucket lid two hours after I put in in the bucket.Yeah I have always used Beersmith and added about a gallon extra to the sparge to be safe. So far so good
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