Thanks Denny. I’m a BIAB devotee and have always wondered how the temperature distribution throughout the mash in the bag/kettle affects the end product. Seems to only be a ‘significant’ temperature deviation between the wort and the grain bed as I ramp up the temperature if I am doing a step mash. I stir the mash but very carefully to limit oxygen introduction.
Generally recirculating systems can step mash. Allow for low mash in temperature and slow rises to mash temperatures.
Filters out tannin containing particles (clean wort to kettle).
Through sight glass, you can use as proxy for alpha conversion.
“It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” - Sherlock Holmes (A. Conan Doyle)
I’ve always been skeptical of the bang-for-the-buck of recirculating systems and their associated equipment costs versus just letting a mash sit in an insulated vessel, which suits my needs just fine.
There are at least two ways to redistribute and homogenize a mixture of solids and liquids: physically redistribute the solids (mix and stir) or redistribute the liquid.
Physically mixing and stirring mash in a tun is pretty difficult and probably uneven, even with the best rake or stirring system. It’s downright poor with just a paddle. Pumping the wort through that mash is a lot easier and more effective (as long as the flow distributor and collector system are well designed).
I went to a RIMS for my brewing over 20 years ago and haven’t regretted it. About 6 or 7 years ago, I finally accepted and understood that avoiding oxygen contact with wort was the secret to producing the malt character that’s found in good commercial German lagers and I implemented a mash cap system that significantly reduces that air contact. That factor is a serious reason to consider RIMS since any sort of stirring at the homebrew level is likely to introduce a lot of air contact to the grist and wort. While I agree that LODO isn’t appropriate for all beer styles, it can certainly make a difference in some.
I recirculate constantly with my RIMS and I’ve wondered if that is ‘tearing up’ my wort and causing problems like reducing the length of protein chains. I think my beers still have body, so I don’t think that occurs. If someone has a differing opinion, I’d like to hear it.
Thanks for taking the time.
Hope someone’s reading.
“It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” - Sherlock Holmes (A. Conan Doyle)
I am reading.
I have an old school three vessel system and use a pump and low propane direct fire to recirculate and raise mash temps. I usually mash in 148±F for a while, then recirc and increase temps to a 158F rest then again to mash out temps. I also take care with introducing extra air by minimal stirring and mash liquor capping the mash - no splashing.
I stir my mash once or twice and don’t pre-boil my dough-in liquor or underlet it into my tun. I also batch sparge so oxygen is there I’m sure. I am reading and know the different perspectives on the hobby.
I’m OK with it and the beers I brew that way. I can’t justify purchasing gear when I have a family to support and other priorities. I suppose I could move more into LODO territory by not stirring and not sparging and still use the same gear.