Water Volume Question

[ScottWa]

So I am still trying to figure out appropriate volumes of water for my system for the different beers I've made and am going to make. I am still relatively new to all gran brewing so bare with me.

Equipment: 15.5 gallon keg for brewpot
10 Gallon Rubbermaid Insulated cooler for mash tun
5 gallon stainless steel brewpot for hot liquor tank

I will be brewing a brown ale tomorrow with 10lbs of grains and am hoping for an even 5 gallons (or a touch more) bottle volume doing a single stage fermentation.

I was thinking of mashing with 4 gal of water which would be just over 1.5 quarts/pound and batch sparging with 4ish gallons. I don't yet have volume markings inside my brewpot so I don't typically know when to stop my runoff.

Here's what my last two batches have yielded:
1) Belgian Style Tripel - 12.5# grain, mashed with 4 gal & sparged with ~4.5 gal. My target was 5.25 gal but actual yield was 4.25 gal. I missed high with OG (target was 1.079 and actual was 1.085) so ended up with higher alcohol than planned. The higher alcohol wasn't a big deal I was just a little bummed that I missed my volume by so much.

2) IPA - 14# grain, mashed with 4.5 gal (just over 1.25 quarts/pound) & sparged with 4.5 gal. my target fermentation volume was 5.25 gal but actual was 4.75+. My target OG was around 1.060 but actual was 1.076 (Oops!) Once again I missed my target volume (ended with just over 4.5 gal after 2ndary fermentation) and my alcohol was quite a bit higher than what I was hoping for.

Should I pay attention to the total water used per pound of grain or just focus more on dialing in mash volumes and sparge volumes separately?

Thanks!

 

[erikpete18]

If I add up your volumes, it seems like you should be good, so maybe you've got a better idea of where your water is going. For #1, I count a total volume of 8.5gal. Subtract grain absorption (12.5*0.12=1.5gal) leaves you with 7gal of water. Now without a kettle measurement, its hard to tell how much deadspace you've got in your mash tun, but I wouldn't think it would be more than 0.5gal, giving you a pre-boil volume of 6.5gal. If you only had 4.25 going into the fermenter, that means you lost 2.25gal to boil off/hop absorption/BK deadspace. How hard are you boiling your wort/how long, and do you have a diptube in your BK? Its possible that without a diptube you're leaving behind another 0.5gal and boiling off 1.75gal (especially if it was a 90min boil).

Similarly with #2, I count 9gal of water minus grain absorption (1.7gal) leaving you with 7.3gal. Subtract another 0.5gal MLT deadspace and you've got about 6.75gal preboil. That's 0.25gal above #1, which makes up for some of the difference in fermenter volume, and the other 0.25gal may have come from slightly less boil-off.

Overall, I'd say you're in the process of dialing in your volumes. Don't worry so much about the water/grain ratio (keep that specific to the style/process you prefer), but increase the amount of sparge water you use to dial in your volumes. The quickest way to do that would be to figure out a way to measure the volume in your BK. A sight glass is a fairly cheap investment if you don't mind drilling into your pot (check out BobbyM's stuff). An easier method is to just get a rod (safe plastic, metal spoon, wood?, etc) that you can stick into the middle of your BK and mark off volumes on the side. That way you can figure out your pre-boil volume (letting you know your MLT deadspace) and post-boil volume (letting you know your boil-off rate). With the fermenter volume, that will give you your BK deadspace, which should give you everything you need. There's also no problem going the easier way and just altering each batch until you're dialed in (for instance adding another 0.5gal total to the next batch,after taking into account grain absorption and seeing where you land).

Finally, just in case you haven't considered it, are you measuring your fermenter volume using markings you've made, or markings already present (like on a bucket)? Apparently a lot of the bucket's volume markings are off by quite a bit, so simply double checking your fermenter measurements might make a difference as well. Good luck!

 

[ScottWa]

Thank you for the very detailed response. I really appreciate your time! I will keep dialing in my system. My markings on my main fermenter I did myself using 1/2 gallon increments. My lines could certainly be off a bit but they should all be relatively close.