Arabinoxylans, which consist largely of pentosan chains, have the ability to form viscous, aqueous solutions that can lead to serious production problems in brewing. Surprisingly, these polysaccharides have received little attention in the brewing literature even though it has been shown that they can be the causal factor of beer haze and filtration problems. This study reports on our investigation of fundamental rheological and filtration properties of arabinoxylan polymers suspended in model buffer systems. The effect of polymer concentration, molecular weight, shear rate and temperature on the rheological properties and filterability of model arabinoxylan dispersions were examined. Model buffer solutions (pH = 4) containing 50 ml/l of ethanol and 5 g/l of maltose were prepared with arabinoxylan polymers of three different average molecular weights (low - 66 kDa, medium - 278 kDa and high - 294 kDa) at polymer concentrations varying from 25 to 5000 mg/l. The apparent viscosities of these model dispersions were first examined in an automated capillary rheometer at 20°C. The resulting rheometric data were analyzed to determine both the intrinsic viscosity [eta] and the critical entanglement concentrations (C (^star)) of polymers in the buffer system. Application of the Mark-Houwink-Khun-Sakurada theory enabled the approximation of the MHKS coefficient (1.20), which indicated the restricted flexibility and stiff worm-like conformation of arabinoxylan polymers in model dispersions. An increasing shear rate sweep (36.7 - 1460 1/s) of arabinoxylan dispersions was performed using a controlled shear rate rheometer with a concentric cylinder fixture. Buffer solutions showed approximate Newtonian fluid behavior, with slight shear thinning behavior observed in the medium and high viscosity arabinoxylan dispersions at gum concentrations above 3000 mg/l. Apparent viscosities at ~350 1/s were then measured at 5, 20, 50 and 75°C. The results showed that the apparent viscosities of arabinoxylan dispersions were independent of shearing time. As expected, the data exhibited an inverse relationship between the viscosity and absolute temperature. The effect of temperature on viscosity was modeled using an Arrhenius-type relationship. The filtration behavior of polymer dispersions was examined using a modified method of Sudarmana et al. (1996, Tech Quart., 33:63), using membrane filters with three different pore sizes. The "Sudarmana transformation" was used to linearize the filtration data and to calculate the maximum filtrate volume (Vmax) and the initial rate of filtration (Qinit). As expected, a decrease in membrane pore size and an increase in gum concentration had a substantial negative effect on Vmax. However, low viscosity arabinoxylan solutions (concentrations above 25 mg/l) had lower Vmax values than medium and high viscosity polymers at the same concentration levels. Interestingly, it was also found that the application of high shear (at shear rates greater than 5000 1/s) substantially increased the Vmax of all arabinoxylan dispersions.