BIAB disaster - bag split open in the kettle mid-mash

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Piggy Smalls

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Hi all

I had a bit of a horror brew day yesterday resulting from my BIAB bag completely splitting open mid-mash. I use a 40L Crown urn and it has lost the cover for the little needle that sits at the bottom of the kettle. I lifted the bag when increasing temp after the acid rest and it must have snagged the needle and torn the bag. I started to notice grain floating in the mash and then as I lifted the bag out of the kettle to inspect the damage the whole grain bed fell out into the kettle. Turns out the entire bottom of the bag had torn.

I managed to finish the mash but I had heaps of problems maintaining a constant consistent temp. I think the pile of grain that kept piling up on the bottom of the kettle when I stopped stirring was stopping the heat travelling up into the top part of the mash. I had a floating thermometer in the mash telling me it was at 65 degrees and I assumed this was my mash temp throughout. When mashing out I gave the whole thing a big stir and I was quite alarmed at how quickly the thermometer got to 78 degrees. I now suspect that the bottom part of the mash was in fact a far bit hotter than the top during the main part of the mash.

I ended up extracting the mash by putting my broken BIAB bag on top of a bucket and using a saucepan to strain the liquid into the bucket. Every few saucepans I would then wrap the grain and squeeze it into the bucket and then discard the grain. This separated all of the grain from the wort and I ended up with my target boil volume. I couldn't rinse the grains as I had started with my full volume for the mash. I did notice afterwards that there was a pretty decent scorch mark at the bottom of the kettle which I think was the result of grain sitting directly on the bottom as I increased the temp. I was a bit worried about the mash temp issue so I added 350g of sugar to the boil to help drive the FG down. After boiling I was pretty close to my target OG and the colour looks pretty standard for this recipe.

My questions are:
A) Has anybody else experienced a BIAB bag blow out and how did they rectify the brew?
B) Would I expect to get many issues from the scorched grain (I detected no smell) or the inconsistent mash temp considering I hit my target OG after topping up with sugar (about 6.5% of total fermentables).
C) Would the unorthodox lautering method cause any astringency issues or would this be pretty much the same as squeezing the bag anyway?

Oh and BTW Its a Maris Otter/Mosaic SMASH (well was til I added the sugar...)
Sounds like a bitch of a brew day Piggy. I did a BIAB on the weekend and underestimated how much strength I needed to lift the bag with 10.5kgs grain and liquor out of the pot. To top it off the grain bag was really slow to drain, but I got there in the end and you did too. Sounds like your brew will be okay. If it smells and tastes okay then it will be. You may need to look around for a stainless steel frame or sieve to sit in the bottom of the pot for the bag to rest on. Love Mosaic, good luck.
a few batches ago I had a brand new bag split at a seam and dumped a big chuck of grain when I removed it .I scooped out what I could with a strainer and just ran with what was left over and the beer came out fine

that said I didn't have heaps in there ,about 500g Id say ,as I realized as I was pulling the bag and managed to minimize the spill
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Thanks Razz and Mongey. It definitely sucks when brew days don't go as planned, I brew to relieve stress, not create it!
I just transferred the wort from the cubes to the fermenter and the colour and smell were great. My OG calculation was a bit off last night (I had to allow for the wort being considerably hotter than 16 degrees) and it actually came in at 1.046 (was aiming for 1.050) so I am glad I added the sugar. Be interesting to see the difference it makes to the finished product. I am hoping it finishes around 1.008 for a dryer than usual pale but still up at 5% ABV. I am thinking those Mosaic hops should shine through with the thinner, dryer finished beer.
You will probably end up with the best beer you have ever made, and unable to ever recreate it. We have all been there in one way or another :) you will still end up with beer 👌
You will probably end up with the best beer you have ever made, and unable to ever recreate it. We have all been there in one way or another :) you will still end up with beer 👌

That's EXACTLY what happened when we accidentally made our youngest........ 😊
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