https://byo.com/article/brewing-with-potatoes-techniques/
When brewing with potatoes, I add the foundation water (the water under the false bottom) to my mash tun then fill the vessel with the crushed grains. I then stir in the whipped potatoes. Unlike when adding flaked maize or other dried starchy adjuncts, adding freshly prepared whipped potatoes to the mash adds heat and a small amount of water to the mash. However, unless you are going titanic with the tubers, this doesn’t amount to a huge difference at mash in. Expect to add slightly less strike water and be prepared to add a small amount of room temperature water as you approach your desired mash thickness due to the added heat from the potatoes. If you dislike “winging it” when brewing, simply stir your whipped potatoes into your strike water prior to mashing in. That way you can heat this “soup” to your normal strike water temperature when mashing in.
Once I’ve mashed in, I brew the beer as I normally would except for stirring the mash a few extra times. I’ve never encountered any problems with the mash sticking during the runoff, even though the potatoes leave behind a small amount of solids in the grain bed.
For recipe calculations, begin with the fact that potatoes have 22% dry weight and of that dry weight, 75% is starch. Assuming that this starch is completely reduced to sugar means that raw potatoes yield about a potential extract of 7.6 points per pound per gallon. (As with the potential extract of malted barley, this number will be modified by your extract efficiency.) Looked at another way, 5.0 lbs. (2.2 kg) of potatoes, with a dry weight of 1.1 lbs. (0.5 kg), have an equivalent potential extract as 1.0 lb. (0.45 kg) of 2-row pale malt.
15.0 lbs. (6.8 kg) Idaho potatoes
{"RecipeId":105716,"RecipeTypeId":10,"OriginalRecipeId":null,"UnitType":"s","IbuFormula":"t","CreatedBy":117615,"Name":"Irish Potato Amber","Description":"https://byo.com/article/brewing-with-potatoes-techniques/\n\nWhen brewing with potatoes, I add the foundation water (the water under the false bottom) to my mash tun then fill the vessel with the crushed grains. I then stir in the whipped potatoes. Unlike when adding flaked maize or other dried starchy adjuncts, adding freshly prepared whipped potatoes to the mash adds heat and a small amount of water to the mash. However, unless you are going titanic with the tubers, this doesn’t amount to a huge difference at mash in. Expect to add slightly less strike water and be prepared to add a small amount of room temperature water as you approach your desired mash thickness due to the added heat from the potatoes. If you dislike “winging it” when brewing, simply stir your whipped potatoes into your strike water prior to mashing in. That way you can heat this “soup” to your normal strike water temperature when mashing in.\n\nOnce I’ve mashed in, I brew the beer as I normally would except for stirring the mash a few extra times. I’ve never encountered any problems with the mash sticking during the runoff, even though the potatoes leave behind a small amount of solids in the grain bed.\n\nFor recipe calculations, begin with the fact that potatoes have 22% dry weight and of that dry weight, 75% is starch. Assuming that this starch is completely reduced to sugar means that raw potatoes yield about a potential extract of 7.6 points per pound per gallon. (As with the potential extract of malted barley, this number will be modified by your extract efficiency.) Looked at another way, 5.0 lbs. (2.2 kg) of potatoes, with a dry weight of 1.1 lbs. (0.5 kg), have an equivalent potential extract as 1.0 lb. (0.45 kg) of 2-row pale malt.\n\n15.0 lbs. (6.8 kg) Idaho potatoes","ImageUrlRoot":null,"StyleId":"15A","StyleName":"Irish Red Ale","BatchSize":5,"BoilSize":6.5,"BoilTime":60,"Efficiency":0.75,"DateCreated":"\/Date(1666188875090)\/","BrewSessionCount":0,"MostRecentBrewSession":null,"Og":1.0505875,"Fg":1.012646875,"Srm":11.975576587378169,"Ibu":45.134259405186,"BgGu":0.89220181675682719,"Abv":4.894340625,"Calories":168,"AverageRating":0,"TastingNoteCount":0,"Fermentables":[{"Per":"81","Amt":"7.5","Ppg":"37","L":"1","Use":"Mash","Id":"567454","IngId":"3","Name":"2-Row - US","CustomName":"","Rank":"1"},{"Per":"8","Amt":"0.75","Ppg":"35","L":"2","Use":"Mash","Id":"567455","IngId":"504","Name":"Caramel Pils - BE","CustomName":"","Rank":"2"},{"Per":"8","Amt":"0.75","Ppg":"33","L":"50","Use":"Mash","Id":"567456","IngId":"40","Name":"Special Roast - US","CustomName":"","Rank":"3"},{"Per":"1","Amt":"0.125","Ppg":"36","L":"23","Use":"Mash","Id":"567457","IngId":"31","Name":"Biscuit Malt - BE","CustomName":"","Rank":"4"},{"Per":"1","Amt":"0.125","Ppg":"34","L":"425","Use":"Mash","Id":"567458","IngId":"507","Name":"Chocolate - UK","CustomName":"","Rank":"5"}],"Hops":[{"Amt":"0.75","Type":"Pellet","Use":"Boil","Min":"60","Day":"0","AA":"9","Ibu":"25.5208520832194","Id":"587207","IngId":"23","Name":"Northern Brewer ","CustomName":"","Rank":"1"},{"Amt":"0.75","Type":"Pellet","Use":"Boil","Min":"30","Day":"0","AA":"9","Ibu":"19.6134073219666","Id":"587208","IngId":"23","Name":"Northern Brewer ","CustomName":"","Rank":"2"}],"Yeasts":[{"Atten":"0.75","Id":"157332","IngId":"229","Name":"Wyeast Irish Ale 1084","CustomName":"","Rank":"1"}],"Others":[],"MashSteps":[],"Steps":[{"Id":"177497","Rank":"1","Text":"15 lbs peeled and cubed potatoes in mash"}]}
https://brewgr.com/Media/img/mug/12_d.jpg
https://brewgr.com/Media/img/mug/12_t.jpg
