Lars and Bob have got it Yetti
. This is actually one of the things in The Misinformation Thread. It's a common question and a good one Yetti as there is a lot of misinformation out there on it. I've written a lot on this over the years but it's all buried away in different posts. Instead of writing a whole lot, what might be more sensible is if I try and dig up some of those buried posts and link them here. (It might help me also see a way of putting the info into a single thread.) [EDIT: Well, I tried
]
There's two myths to negate here. The first is sparging increases kettle efficiency. The second, which I've never heard before but you have mentioned, is that it increases quality.
Sparging (or dunking) does not increase quality.
I think the best thing I have written on this aspect would be a little series of stories called "The Sweet Liquor Shop" posts. These explain the different methods of producing sweet liquor and corrects a few myths. Here you will learn the difference between true no-sparging, pure BIAB (passive sparging)and traditional brewing (active sparging) methods.
Sweet Liquor Shop 1
Sweet Liquor Shop 2
Sweet Liquor Shop 3
Sparging (or dunking) does not increase kettle or any other type of efficiency.
This is the most common myth and it is a very hard one to understand psychologically. There are many things which lead us to believe that sparging would wash more 'sugars' out of our grain bed. What's more, you'll constantly read posts on how someone's "efficiency" improved when they sparged. So what's going on here?
Firstly, it is natural to believe that sparging would be better. For example, our clothes in the washing machine are washed and then usually rinsed twice just as a lot of batch spargers do. But, a washing machine is not the same as brewing. The washing machine has a spin cycle before and after each rinse and this makes a big difference. Imagine if your washing machine just let the dirty water drain out. iF you stop and think about it, it actually makes no difference whether you put the total amount of water in to the wash first (as in pure BIAB) or in stages (as with sparging of any sort). If you collected the water that came out of the wash, you would find it to be just as dirty whether the water was added in a single hit or in three stages. In other words, you would still wash the same amount of dirt (sugar) out of the clothes.
The above concept can be a little non-intuitive to get your head around but we also have tested it in real life. THere's a thread on there where I did six side by side brews of active sparging and passive sparging (pure, full-volume BIAB). On average, thee was a 1% difference in kettle efficiency which basically means nothing. It's not the first time I have done side by sides on this.
There's a few erroneous reasons why you'll often see posts that say their efficiency improved with sparging. I just want to cover one here. Imagine a new BIABer had been doing a 60 minute mash (as they are often mistakenly told to do). Imagine then that they do a 60 minute mash followed by a thirty minute dunk while heating their main body of sweet liquor to boiling point. Their efficiency into kettle will go up but not because they are sparging. It is going up because they have increased their mash time - nothing more. If they had just mashed with all their water for 90 minutes, they would have had the same result. Such posts are all variations of this. The numbers are based on a comparison of just two brews and nearly always, something has changed in the process, e.g. the second brew is a ower gravity brew.
In what situations should I sparge?
The only time when it is really appropriate to sparge is when you are unable to full-volume mash and you are doing a very high gravity brew or are wishing to avoid a lot of dilution.
The BIABacus is a great tool, the only tool, that shows you the interplay between grain bill, sparging, dilutions and vessel volumes. The first thing we need to work from is the understanding that if you can fit all your water in the kettle at the start of the mash, then do so because thee is no advantage not to.
If your kettle is not big enough to handle all the water in the beginning, if you do sparge, on a normal gravity brew, after you pull the bag, there's actually not going to be that much room in the kettle to even add much water you actively sparge. So, the question then becomes, "Is it worth an extra heat source and vessel to handle this sparging process to save a bit of grain?" The higher the grain bill, the more likely the answer is to be, "Yes," simply because there will be more space available in the kettle after the bag is pulled. That is the only reason.
So, sparging should be viewed as very much a last resort method.
What else are we missing here Yetti? You or anyone else, please ask any questions you have on this here.
PP
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, and would like to start to polish my method.
