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Old 02-11-2013, 03:05 AM   #1
allgrainpa
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It appears that my evaporation rate is near the 20-25% after a 60 minute boil. The obvious answer appears to be to add a lid during the boil to decrease the amount of water im losing during my boil but i consistently read that you dont need a lid on during the boiling process. I maintain a nice rolling boil but by no means is it excessive. How do I minimize the amount of wort im losing during the boiling process if not be the use of a lid? What are the advantages/disadvantages of using a lid during the boil?

thank you in advance

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Old 02-11-2013, 03:12 AM   #2
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Don't cover the boil. Lots of stuff happening. I will let someone smarter than I am respond to this. But I believe it is a dms issue.

If you end up with too little wort after the boil you can top up with boiled and cooled water to the volume you need. Or just anticipate and use more water at the start of the boil.

Once you have your system dialed in you can anticipate boil off rates and get your volumes down. Good luck!

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Old 02-11-2013, 03:18 AM   #3
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Dms issue?

Also if i add water after the boil this will effect my OG and cause me to undershoot/overshoot my attended gravity. For example a recent AG brew with very heavy boiling lead to a large amount of evaporation leaving me with only 3 gallons instead of the intended 5. I added the needed 2 gallons of water after the boil giving me a total of 5 galons but my OG was much lower than what I wanted. Thus by adding water this will effect my OG and effect the outcome of my targeted recipe, correct?

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Old 02-11-2013, 03:27 AM   #4
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Originally Posted by allgrainpa View Post
Dms issue?

Also if i add water after the boil this will effect my OG and cause me to undershoot/overshoot my attended gravity. For example a recent AG brew with very heavy boiling lead to a large amount of evaporation leaving me with only 3 gallons instead of the intended 5. I added the needed 2 gallons of water after the boil giving me a total of 5 galons but my OG was much lower than what I wanted. Thus by adding water this will effect my OG and effect the outcome of my targeted recipe, correct?
No, the amount of sugar in the kettle won't change.

In other words:
1) starting at 7 -> boiling to 3 -> filling to 5
2) starting at 7 -> boiling to 5
...will give you identical gravities in the end.
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Old 02-11-2013, 03:44 AM   #5
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As MalFet said above and high boil off off is your friend, you can oversparge, get better extraction and then boiloff extra water, its very useful for high gravity beers where efficiency goes down

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Old 02-11-2013, 03:48 AM   #6
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please excuse my ignorance but im trying to wrap my head around this.

My understanding is if I have a fixed amount of sugar and I place that amount in 2 gallons of water it would be much more concentrated than if i placed the same amount of sugar in 10 gallons of water. Not sure how gravity and concentration equate out but it seems this would have a direct result in my OG. In other words the OG is a reading of the amount of sugar i have in my wort and if I have same amount of sugar in 2 gallons versus 10 then my OG would differ between quantities of liquid.

if it is that easy to get 5 gallons of water then why so much trouble trying to calculate how much preboil water is needed to end up with desired end product. We could all just make a "concentrate" and just add water to end up with the 5, 10, etc amount of wort

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Old 02-11-2013, 03:56 AM   #7
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let me ask this if i add the needed water to get a total of 5 gallons does it matter when i add the water. can i add it after wort has been cooled just prior to pitching or is it better to add just prior to completion of the boil?

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Old 02-11-2013, 04:02 AM   #8
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Well, most of us start out with much more wort than we need anyway because of the amount it takes to mash and sparge. That may not be the best wording but maybe you can understand. For a 5 gallon batch, I end up with 7-8 gallons of wort after sparging is complete. So it works out great that I'm going to boil off 2-3 gallons. I don't usually end up with "exactly" 5 gallons either. So it's 4.9, or a little over 5, I don't freak out about it but some guys are very particular about being at a certain OG, for me when the boil is over it is what it is until the yeast take over.

One big reason why full volume boils are encouraged over partial volume boils, (which a lot of extract brewers do), is because it can greatly improve head retention and probably a lot of other things I don't know about.

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Old 02-11-2013, 04:06 AM   #9
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You have a lot of questions here....I'll try to answer a few

If you boil off, you are losing water only, no sugars. So whether you start with 10 gallons and boil off 5 or start with 5.5 and boil off .5 it is the same amount of sugars. That's what Malfet was saying as well. Yes, it is more concentrated and hence has a higher OG, but you were asking about boil off, not OG.

The hop utilization rate is different when you boil different amount of liquid. That's why you need to know how much you will lose and not just top off.

If you want to just use water at the end and basically do a partial boil, that is fine, but you do need to boil the water for sterilization instead of just dumping from the faucet. 10 minutes will do the trick - but again your hop utilization will be different.

Boil off is a matter of RH more than anything else if your boil is the good. What's is the temp you are brewing at? Is it super cold?

I suggest figuring this boil rate out. I really think your figures are off - you can't be the only one who brews ad gets 25% rate boil off. You are going down a level (IMO) by adding just water to the end.

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Old 02-11-2013, 12:38 PM   #10
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Quote:
Originally Posted by allgrainpa View Post
let me ask this if i add the needed water to get a total of 5 gallons does it matter when i add the water. can i add it after wort has been cooled just prior to pitching or is it better to add just prior to completion of the boil?
Ideally, you don't want to be adding much water at all. Your boiloff rate is very high, and it would be worth figuring out why that is. In any case, if it is going to be consistently that large, you should simply adjust your preboil volume to accommodate. In other words, if you're boiling off two gallons over an hour, you should plan to start with 7 gallons so you end up with 5.
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